rnd100diagrams

100 random diagrams, manually analyzed

wTot = 16, wPawns = 2, wProms = 6
bTot = 13, bPawns = 3, bProms = 2
pieceCnts = [1,2,3,6,2,1,1,3,3,2]
--     corresponding to [K,Q,R,B,N,k,q,r,b,n]
B r . k . B K .
N . R B p . b R
. . . . q . . b
B . . B P . p .
. . p r n . . .
. R b r . N . Q
. n . . . . P Q
. . . . . B . .
wpx = 8-2-6 = 0    maxuwp = 3+3-6 = 0
bpx = 8-3-2 = 3    maxubp = 0+3-2 = 1
minopp = max 2-0 3-1 = 2
White Kg9 in check by qe6
Black kd8 not in check
Illegal because wProms=6 requires missing pawn files to come in 3 adjacent pairs
(e.g. if 2nd oppose were on f instead of g file)

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,2,4,2,3,1,5,2,2,3]
. . . R q b . .
q . . r q B Q K
. . . Q . R k .
q . p . . n . .
. . . b R . . .
N p . . . . N .
R . r P N B . q
. n . n . . . .
White Kh7 in check by kg6
Black kg6 in check by Kh7
Illegal due to adjacent kings

wTot = 14, wPawns = 2, wProms = 5
bTot = 14, bPawns = 3, bProms = 4
pieceCnts = [1,1,6,1,3,1,3,1,3,3]
k n . . N R . .
b . . p R . r .
. n n P B p . Q
q N . q . R . .
R . R . b . b .
. . . K . . . .
. . . p . P . .
. . . R N q . .
White Kd3 in check by be4 and qd5
Black ka8 not in check
Illegal due to impossible double check on king

wTot = 15, wPawns = 3, wProms = 4
bTot = 13, bPawns = 3, bProms = 3
pieceCnts = [1,4,2,3,2,1,2,3,1,3]
n . . N . Q . Q
. Q r p . . . .
. . . . q . B q
. b Q P p r . .
. . . . . n K .
P B . . R . k .
. . p . P . N .
n B r . . R . .
White Kg4 in check by kg3
Black kg3 in check by Kg4
Illegal due to adjacent kings

wTot = 13, wPawns = 2, wProms = 3
bTot = 14, bPawns = 3, bProms = 4
pieceCnts = [1,2,2,3,3,1,3,1,3,3]
. . . . . . . .
p B B . . P . .
q N . . b . Q q
K . N N . . . P
. r Q . p n . p
. . . k n b . .
q n . . . B b .
R . . . . . R .
White Ka5 in check by qa6 and qa2
Black kd3 in check by Qc4
Illegal due to both kings in check

wTot = 15, wPawns = 0, wProms = 7
bTot = 13, bPawns = 3, bProms = 2
pieceCnts = [1,4,2,2,6,1,1,2,2,4]
. n K . . . . .
. p . N . R . N
q . . k Q . B .
p Q Q . n r b .
N . . . . b . p
. . . . . N . n
N N . . r . n .
. . . . R Q B .
White Kc8 not in check
Black kd6 in check by Qc5 and Qe6
Illegal due to impossible double check on king

wTot = 12, wPawns = 1, wProms = 3
bTot = 16, bPawns = 3, bProms = 5
pieceCnts = [1,1,5,2,2,1,2,2,2,6]
n . b b . . . .
. . . . . . . q
n p . . . n . r
. B P . . k q R
B n R R R . . .
p N . r . p . n
. . n Q R . . .
N . . . . . . K
wpx = 8-1-3 = 4    maxuwp = 0+4-3 = 1
bpx = 8-3-5 = 0    maxubp = 4+4-5 = 3
minopp = 1-1 = 3-3 = 0
White Kh1 not in check
Black kf5 not in check
Illegal due to white bishops of same color and no spare promotions

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,2,2,2,6,1,3,2,2,3]
. R . . n . N b
. k . B . . . .
. q N N . P . q
. . P p Q . . .
. n n N . b . N
. N . . q r K .
B . . . . p R Q
. . . r . . . .
White Kg3 in check by rf3 and bf4
Black kb7 in check by Rb8 and Nd6
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,1,4,2,4,1,2,5,2,3]
. . N . . n r n
n R . k N . p .
. . b . B K . .
r . B R p r N .
. . . . . . . .
. P . r . . N .
. . . Q q q . .
. . . R b . R r
White Kf6 in check by rf5 and pg7
Black kd7 in check by Rb7 and Rd5 and Be6
Illegal due to both kings in check

wTot = 14, wPawns = 1, wProms = 6
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,0,2,4,6,1,1,4,2,3]
r . . . . . . .
. . . . R . r .
. . n . K N N B
. . b N . p . q
. B p . . r k .
. R . . . r . N
. P b . . . . .
B n N B . n N .
wpx = 8-1-6 = 1    maxuwp = 3+5-6 = 2
bpx = 8-2-3 = 3    maxubp = 1+5-3 = 3
minopp = 1-2 = 2-3 = -1
White Ke6 not in check
Black kg4 in check by Nf6
Illegal due to Ba1 trapped by Pb2

wTot = 14, wPawns = 1, wProms = 5
bTot = 14, bPawns = 3, bProms = 3
pieceCnts = [1,4,4,2,2,1,4,2,2,2]
. q Q . B . . n
. q . . P Q . R
q . . . . p p .
. n p . . . b .
. . N r . N R q
. b K . . R . k
. Q . . . B . Q
. . . . . . r R
White Kc3 in check by nb5
Black kh3 in check by Qh2 and Rf3 and Nf4
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,2,5,2,3,1,2,4,4,2]
. n q . . . r B
P K . q n . b .
Q . N . . r N .
. . R Q . . . N
. . R b . . . .
. . R b . . . .
. . P . b R . R
B r . . . k r .
White Kb7 in check by qc8 and qd7 and rb1
Black kf1 in check by Rf2
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 1, bProms = 4
pieceCnts = [1,1,6,2,3,1,2,2,5,2]
. . B . R q N b
P . n B . . . .
. . b r . . . .
q . . . . N p b
k . . . . . . N
. . . . r b P .
Q . . K . . . b
. R R R R . n R
White Kd2 in check by qa5
Black ka4 in check by Qa2
Illegal due to both kings in check

wTot = 16, wPawns = 3, wProms = 5
bTot = 12, bPawns = 4, bProms = 1
pieceCnts = [1,2,3,3,4,1,2,1,2,2]
. . Q . n . B q
. . q P N . b .
. . p . N . . p
p P r B b . . P
R . . . . . N .
B . p Q K R . .
n . . . . R . .
N . . k . . . .
wpx = 8-3-5 = 0    maxuwp = 3+4-5 = 2
bpx = 8-4-1 = 3    maxubp = 0+4-1 = 3
minopp = 3-2 = 4-3 = 1
White Ke3 not in check
Black kd1 in check by Qd3
Illegal due to no white pieces captured to double black c pawns

wTot = 13, wPawns = 2, wProms = 3
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,3,2,2,3,1,3,4,3,2]
. . r . . . . .
r . Q . . p . .
r k . . . N B .
q . K r B Q R .
. q b . . b . P
. q . N . n p R
P . . . n . N .
. . b . . . Q .
White Kc5 in check by kb6 and qa5
Black kb6 in check by Kc5 and qc7
Illegal due to both kings in check

wTot = 16, wPawns = 1, wProms = 7
bTot = 11, bPawns = 3, bProms = 2
pieceCnts = [1,5,2,4,3,1,2,1,1,3]
. . . . . . . B
q . Q . r B . k
. . . . . n . .
p N n K Q N . .
. N b B Q P . R
p q p . Q n . .
. . Q . . . . .
. . B . R . . .
White Kd5 in check by bc4 and nf6
Black kh7 in check by Rh4
Illegal due to both kings in check

wTot = 16, wPawns = 1, wProms = 7
bTot = 12, bPawns = 3, bProms = 1
pieceCnts = [1,5,5,2,2,1,2,2,2,2]
. Q R . . . . B
. B . n . q r .
R . . K . Q . .
. p R N . . . .
. p Q . . . Q .
. . . p Q N b R
. b P R . . . .
k r . q . . n .
White Kd6 in check by bg3
Black ka1 in check by Ra6
Illegal due to both kings in check

wTot = 15, wPawns = 4, wProms = 3
bTot = 13, bPawns = 1, bProms = 4
pieceCnts = [1,3,2,2,3,1,1,2,4,4]
. n . . . . . r
n . n . k . . .
P . . . R . N p
r Q . . P . n .
. N P . B K B .
. b . R . q b Q
b P . . Q . . .
. . . . N b . .
White Kf4 in check by qf3 and bg3
Black ke7 in check by Re6 and Ng6
Illegal due to both kings in check

wTot = 16, wPawns = 1, wProms = 7
bTot = 12, bPawns = 3, bProms = 1
pieceCnts = [1,5,4,2,3,1,2,2,2,2]
B . Q N B Q . .
Q . R . Q n . p
r . P . . . Q .
. q . . . . K .
p k . R . . . q
. . . N . r . b
. . . . . p b R
. n . . R N . .
White Kg5 in check by qh4 and nf7
Black kb4 in check by Rd4 and Qe7
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,1,5,3,3,1,2,3,2,5]
. R n . R . . Q
. N . r R P . .
n N n b . P . .
. . R . B . . B
. . b N . . . .
n R . k . . . n
. q . . . . . r
K . q B . . . r
White Ka1 in check by qb2 and qc1
Black kd3 in check by Rb3
Illegal due to both kings in check

wTot = 15, wPawns = 1, wProms = 6
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,1,3,4,5,1,2,3,2,3]
. . . . . . . .
. . n . . . q .
. . . B P k b .
. K . . n N . r
Q b . . . B p .
. . . . . r . B
R R r N . p B .
. N n N q . R N
wpx = 8-1-6 = 1    maxuwp = 3+4-6 = 1
bpx = 8-2-3 = 3    maxubp = 1+4-3 = 2
minopp = 1-1 = 2-2 = 0
White Kb5 in check by nc7
Black kf6 not in check
Legal with white to move?!

wTot = 12, wPawns = 1, wProms = 3
bTot = 16, bPawns = 1, bProms = 7
pieceCnts = [1,1,3,3,3,1,2,4,5,3]
. k b b . . . r
. r p P . . . N
q . n . . . K B
Q N R . B n . .
n . b r . . . .
r . N . . . . .
B . b . . b . .
q R . . . R . .
wpx = 8-1-3 = 4    maxuwp = 0+4-3 = 1
bpx = 8-1-7 = 0    maxubp = 4+4-7 = 1
minopp = 1-1 = 1-1 = 0
White Kg6 not in check
Black kb8 not in check
Legal?!

wTot = 16, wPawns = 3, wProms = 5
bTot = 12, bPawns = 2, bProms = 3
pieceCnts = [1,2,2,3,5,1,2,1,4,2]
. . B . . . . .
. . . b b . p .
Q p N . P . . r
Q . P . . . P .
. b N . B n . q
. . N b n . N .
k K . . R q . .
R N . B . . . .
White Kb2 in check by ka2
Black ka2 in check by Kb2 and Ra1 and Qa5 and Nc3
Illegal due to adjacent kings

wTot = 16, wPawns = 4, wProms = 4
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,1,3,3,4,1,4,2,2,2]
. B R . q . . K
. . . . N P p .
b . . N n k . q
. . r N . . . q
B q . B . . . b
. . . . . R P r
P P N . . . R Q
. . . . . . . n
White Kh8 in check by qe8 and qh6
Black kf6 in check by Nd5 and Bd4 and Rf3
Illegal due to both kings in check

wTot = 14, wPawns = 5, wProms = 2
bTot = 14, bPawns = 1, bProms = 5
pieceCnts = [1,2,1,3,2,1,3,4,2,3]
r . . b . . . r
. k . . . Q n .
. . . n . . . P
r P . B B . p n
. r P B . . P .
b . . . . . P q
. . R . . N . Q
q . . K q . N .
White Kd1 in check by qe1 and qa1
Black kb7 in check by Bd5 and Qf7
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,1,4,3,3,1,3,4,3,2]
b . . R . . . B
. K . k R p . .
. n . . p R . R
. b . b . . . .
N q r B r . B .
P . N r . . q q
. . . . . . . .
. Q . n N . r .
White Kb7 in check by ba8 and bd5
Black kd7 in check by Rd8 and Re7
Illegal due to both kings in check

wTot = 14, wPawns = 2, wProms = 4
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,3,4,2,2,1,2,3,4,1]
. . . . K . . .
B . . b R R . .
p . P n . R Q .
q Q b P . b . q
r . . . . Q . .
. . . . . . B .
. r R p . . N b
. . . k N . r .
White Ke8 in check by bd7 and nd6
Black kd1 not in check
Illegal due to impossible double check on king

wTot = 13, wPawns = 3, wProms = 2
bTot = 15, bPawns = 1, bProms = 6
pieceCnts = [1,2,2,2,3,1,5,2,3,3]
. . . B . . . q
. R P p . . . .
N R . P . . B .
N . q . N P n .
n . Q r . . q .
. k b . . . . .
b . . b . . . q
K q . . r n Q .
White Ka1 in check by bc3 and qb1
Black kb3 in check by Na5 and Rb6 and Qc4
Illegal due to both kings in check

wTot = 15, wPawns = 1, wProms = 6
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,4,3,3,3,1,2,3,3,2]
. . R Q N . . Q
. p . n b B . n
. . N r . R . q
Q B . . . Q . P
r . . . . . K .
. B . r . p . b
. . R . b N . .
. q . k . . . .
White Kg4 in check by bh3 and ra3
Black kd1 in check by Nf2
Illegal due to both kings in check

wTot = 14, wPawns = 2, wProms = 4
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,1,6,2,2,1,0,3,4,3]
. . . R . b . .
. . B . . . . .
. R . n . b . R
. p N . K k P .
Q R B . r . N .
r . r b n R n R
. . p . . . P .
. . . . b . . .
White Ke5 in check by kf5
Black kf5 in check by Ke5
Illegal due to adjacent kings

wTot = 12, wPawns = 0, wProms = 4
bTot = 15, bPawns = 1, bProms = 7
pieceCnts = [1,2,2,5,2,1,3,3,1,6]
n . B k n . n .
Q . . . . p . B
r n q n N . r .
. . Q . . . . .
r . . . . . . .
N . . . B R n K
. . . q B . . R
B . . b . . . q
wpx = 8-0-4 = 4    maxuwp = 0+5-4 = 1
bpx = 8-1-7 = 0    maxubp = 4+5-7 = 2
minopp = 0-1 = 1-2 = -1
White Kh3 not in check
Black kd8 in check by Ne6
Legal with black to move?!

wTot = 14, wPawns = 0, wProms = 6
bTot = 14, bPawns = 0, bProms = 6
pieceCnts = [1,1,2,4,6,1,5,3,2,3]
q B . N . R N .
. . B r k . . .
. . . . . q . r
. . b . . B N .
. n N N . K . b
. q . . . R Q q
n N . . . . B .
. r . . . . n q
wpx = 8-0-6 = 2    maxuwp = 2+4-6 = 0
bpx = 8-0-6 = 2    maxubp = 2+4-6 = 0
minopp = 0-0 = 0-0 = 0
White Kf4 not in check
Black ke7 in check by Ng8
Legal with black to move?!

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,1,4,3,4,1,2,5,3,2]
. . . . . N . .
n . . . . Q r r
R . b . K . k .
. r r . b N . .
. N . q R B P .
. P . q . B . .
B . . R R . . .
. . b r . N n .
White Ke6 not in check
Black kg6 in check by Qf7 and Nf8
Illegal due to impossible double check on king

wTot = 13, wPawns = 1, wProms = 4
bTot = 14, bPawns = 3, bProms = 3
pieceCnts = [1,3,4,2,2,1,2,4,2,2]
. . . Q b . . B
. . . R p . r .
P . B N . . . .
. . . n r . . Q
. . . k . . N .
R . r . . . p R
. p . . . . . r
q Q q K b R . n
wpx = 8-1-4 = 3    maxuwp = 2+5-4 = 3
bpx = 8-3-3 = 2    maxubp = 3+5-3 = 5
minopp = 1-3 = 3-5 = -2
White Kd1 in check by qc1 and Nf8
Black kd4 not in check
Legal with white to move?!

wTot = 16, wPawns = 1, wProms = 7
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,3,4,4,3,1,2,2,2,4]
. n K . . . . k
. B . Q . n R .
. . . . . . . .
B Q . B N B p .
. . P r b . . q
. N N n R . . q
n b r . . . . .
. R Q . R . . .
wpx = 8-1-7 = 0    maxuwp = 4+4-7 = 1
bpx = 8-1-3 = 4    maxubp = 0+4-3 = 1
minopp = 1-1 = 1-1 = 0
White Kc8 not in check
Black kh8 not in check
Legal?!

wTot = 16, wPawns = 2, wProms = 6
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,2,4,2,5,1,1,5,2,2]
n N . R r . . B
. . . r . R . Q
. . . r . . . .
N p . K . . . r
. . b . . Q N P
q . n r B P . .
k . . R . . N .
. N . R b . . .
White Kd5 in check by rd6 and bc4 and nc3
Black ka2 in check by Rd2
Illegal due to both kings in check

wTot = 14, wPawns = 0, wProms = 6
bTot = 14, bPawns = 2, bProms = 4
pieceCnts = [1,2,5,2,4,1,1,2,5,3]
n R . b . . Q R
B . . N . . . .
R . r b . N . Q
n q . K . . . b
. R B b . . . p
. . . . . N b .
n k p . N r . .
. . . R . . . .
wpx = 8-0-6 = 2    maxuwp = 2+4-6 = 0
bpx = 8-2-4 = 2    maxubp = 2+4-4 = 2
minopp = 0-0 = 2-2 = 0
White Kd5 in check by qb5
Black kb2 in check by Rb4
Illegal due to both kings in check

wTot = 12, wPawns = 3, wProms = 2
bTot = 16, bPawns = 3, bProms = 5
pieceCnts = [1,3,1,2,2,1,2,3,4,3]
r n . q . . n .
B . . Q . . . p
. k . . . . . P
. p b K . R . .
P . Q . r b . .
b . . b r P . p
. . N . . . q .
wpx = 8-3-2 = 3    maxuwp = 0+4-2 = 2
bpx = 8-3-5 = 0    maxubp = 3+4-5 = 2
minopp = 3-2 = 2-2 = 1
White Kd4 not in check
Black kb5 in check by Ba6
Illegal due to doubled h pawn requiring extra capture

wTot = 15, wPawns = 2, wProms = 5
bTot = 14, bPawns = 3, bProms = 3
pieceCnts = [1,2,3,4,3,1,1,3,3,3]
. . . B . . . .
r . . N p Q . R
r K . p n R . .
. . p n . r k .
Q B . . P . q .
. . P . R . b .
. b . . B b N .
N . B . . . . n
White Kb6 in check by ra6 and nd5
Black kg5 not in check
Illegal due to impossible double check on king

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 1, bProms = 6
pieceCnts = [1,1,4,4,2,1,2,6,3,2]
. R N B . q r .
. . . . . . . .
q . . r . R r .
R n K B . n . .
. r . . . B P .
b Q k . b N . p
. . r . B . r .
. . . . b . R .
White Kc5 in check by be3
Black kc3 in check by Qb3
Illegal due to both kings in check

wTot = 16, wPawns = 1, wProms = 7
bTot = 12, bPawns = 2, bProms = 2
pieceCnts = [1,5,2,4,3,1,2,2,3,2]
. . . b Q r k .
. . Q B B R . .
. b p . . . . .
q . K . B . N .
. p B . n . . .
. r . R N Q Q .
. N q . n . . P
. Q b . . . . .
White Kc5 in check by bb6 and qa6 and ne4
Black kg8 not in check
Illegal due to impossible double check on king

wTot = 13, wPawns = 1, wProms = 5
bTot = 14, bPawns = 1, bProms = 6
pieceCnts = [1,2,5,3,1,1,2,6,1,3]
. . r . . R . q
r . . R . . n r
. . . . P . r .
r R . q p . . .
. . . . B . n b
. . K n . R Q B
Q . . . B . r .
N . R . k . . .
White Kc3 in check by rc8
Black ke1 in check by rc1 and Qg3
Illegal due to both kings in check

wTot = 15, wPawns = 0, wProms = 7
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,3,3,2,6,1,2,2,3,3]
N . B N R r N .
r R . . K . . .
N . . . . . k .
. p Q p b . . n
. . . . b q Q .
Q . N . . R . n
. B . . N . . .
n . q . . . . b
wpx = 8-0-7 = 1    maxuwp = 3+4-7 = 0
bpx = 8-2-3 = 3    maxubp = 1+4-3 = 2
minopp = 0-0 = 2-2 = 0
White Ke7 not in check
Black kg6 in check by Qg4
Legal with black to move?!

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 0, bProms = 7
pieceCnts = [1,1,4,3,3,1,3,3,5,3]
. . . . . B . N
. . . q . b b q
. . . K k . n .
b . . . B P N .
. . b R . . . n
r . R R . . . r
. . n Q . R b .
r q . B . . N .
White Kd6 in check by ke6
Black ke6 in check by Kd6
Illegal due to adjacent kings

wTot = 12, wPawns = 0, wProms = 4
bTot = 16, bPawns = 3, bProms = 5
pieceCnts = [1,3,3,2,3,1,3,3,4,2]
. q . . Q . N b
b r . . . q . p
Q . q n . . . .
R . . . b . p .
. K . N B . b .
B . r N R . . .
. . p . . n . .
R . . Q . r . k
White Kb4 in check by rb7
Black kh1 in check by Be4
Illegal due to both kings in check

wTot = 14, wPawns = 3, wProms = 3
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,2,3,3,2,1,4,2,1,3]
. B n . B q . R
n R . . Q k . .
P p . R r . q .
. . . . . q . .
. . n q . B . .
. . . P . r . P
N . . N b . p K
. . . . Q . . .
White Kh2 not in check
Black kf7 in check by Be8 and Qe7
Illegal due to impossible double check on king

wTot = 13, wPawns = 2, wProms = 3
bTot = 15, bPawns = 1, bProms = 7
pieceCnts = [1,3,2,2,3,1,4,6,1,2]
. . . K . . . .
. R . . . . r .
. r R . q . . B
. p P Q r . r .
q q . Q . n . B
N P . N . . . k
. r . . N b . q
. . . . . n r Q
wpx = 8-2-3 = 3    maxuwp = 0+4-3 = 1
bpx = 8-1-7 = 0    maxubp = 3+4-7 = 0
minopp = 2-1 = 1-0 = 1
White Kd8 not in check
Black kh3 not in check
Illegal due to white same colored bishops requiring extra promotion

wTot = 14, wPawns = 4, wProms = 3
bTot = 14, bPawns = 2, bProms = 4
pieceCnts = [1,2,1,2,4,1,2,4,2,3]
. . q . . . . N
K b P n . . Q N
. k p . Q . . B
. . r n p R . P
q . B . . . N b
n P P . . . . .
. . r . r . . .
. . . r . N . .
White Ka7 in check by kb6
Black kb6 in check by Ka7
Illegal due to adjacent kings

wTot = 14, wPawns = 0, wProms = 6
bTot = 13, bPawns = 0, bProms = 6
pieceCnts = [1,6,3,2,2,1,3,2,6,1]
b . . . . K . Q
. R . . . b Q Q
q Q . b . . q .
Q R Q . b . r .
. . b . B . . .
. . . . N . . .
. . N r B . k .
. . b n . R q .
White Kf8 in check by bd6
Black kg2 in check by Ne3 and Be4
Illegal due to both kings in check

wTot = 13, wPawns = 0, wProms = 5
bTot = 15, bPawns = 3, bProms = 4
pieceCnts = [1,1,5,4,2,1,1,2,6,2]
. . r . . . . .
p . . . R . . q
. . Q B . . K B
. b b . . B k b
. . p . n N R .
. r B . . . b n
N . . b . . p R
. b . . R . . R
White Kg6 in check by kg5
Black kg5 in check by Kg6
Illegal due to adjacent kings

wTot = 12, wPawns = 2, wProms = 2
bTot = 16, bPawns = 1, bProms = 7
pieceCnts = [1,1,3,3,2,1,3,3,3,5]
. . . . q r . r
B . n . . b k q
. . . . p . R .
. b . . . Q . .
. B b n B R n .
P . . n r K . n
. . . . P . . .
. N . N . q . R
White Kf3 in check by re3 and qf1 and nd4
Black kg7 in check by Rg6
Illegal due to both kings in check

wTot = 16, wPawns = 2, wProms = 6
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,2,2,6,3,1,1,3,4,2]
. . Q . n . . .
k . . . . P B p
. . B b . . . B
N n . . q Q . .
B b b B . P r .
. . . . . . R b
. K . N R N . .
r B r . . . . .
wpx = 8-2-6 = 0    maxuwp = 4+4-6 = 2
bpx = 8-1-3 = 4    maxubp = 0+4-3 = 1
minopp = 2-2 = 1-1 = 0
White Kb2 not in check
Black ka7 in check by Bd4
Legal with black to move?!

wTot = 14, wPawns = 3, wProms = 4
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,4,2,1,3,1,3,3,1,3]
N . . . . . . .
Q p . N n . P n
q . . . . . Q .
r . k P r q . B
. P R p n . . .
. . N . . Q . .
. . . Q . . . R
K b q . r . . .
White Ka1 in check by ra5
Black kc5 in check by Qa7 and Nd7 and Pb4 and Rc4
Illegal due to both kings in check

wTot = 15, wPawns = 3, wProms = 4
bTot = 13, bPawns = 3, bProms = 2
pieceCnts = [1,2,3,2,4,1,1,2,2,4]
n . . n Q N . .
p K B . . . P N
. . p . p . . .
. B r P q b k r
. . Q N . . . .
. n . R . P . .
N . . . . . b .
. . . . . n R R
White Kb7 in check by nd8
Black kg5 in check by Nh7
Illegal due to both kings in check

wTot = 14, wPawns = 0, wProms = 7
bTot = 13, bPawns = 4, bProms = 2
pieceCnts = [1,4,1,6,2,1,0,3,2,3]
n B K . b . B .
N p Q . B . B .
. b . . p . . p
. . . . . r . .
. Q . Q r . . .
n B n . . . R .
. Q . . k . p .
r . N . . . B .
wpx = 8-0-7 = 1    maxuwp = 2+5-7 = 0
bpx = 8-4-2 = 2    maxubp = 1+5-2 = 4
minopp = 0-0 = 4-4 = 0
White Kc8 not in check
Black ke2 in check by Nc1 and Qb2
Illegal due to impossible double check on king

wTot = 14, wPawns = 2, wProms = 5
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,2,4,1,4,1,2,2,6,2]
. n . b . B . q
. k . . R b b b
n . . . . . P .
. b . . . Q N .
. . . . N . . b
. R . . R . r .
Q . . . . . r P
q N . K R . . N
wpx = 8-2-5 = 1    maxuwp = 3+5-5 = 3
bpx = 8-0-5 = 3    maxubp = 1+5-5 = 1
minopp = 2-3 = 0-1 = -1
White Kd1 not in check
Black kb7 in check by Re7
Legal with black to move?!

wTot = 14, wPawns = 5, wProms = 2
bTot = 14, bPawns = 3, bProms = 3
pieceCnts = [1,0,2,2,4,1,3,2,3,2]
. N . . . N . k
. . P q . b p R
p . N . . . p .
. . b q . . . .
. r n . . P P .
. . . R N B r P
. P B . . . q .
n . . . . b . K
White Kh1 in check by qg2
Black kh8 in check by Rh7
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 6
bTot = 12, bPawns = 2, bProms = 3
pieceCnts = [1,4,1,3,4,1,0,4,2,3]
Q B r . . . n .
r . . b . N . n
. k . Q . N . r
. P . Q P p Q .
K . N . . . B .
. . n R . . . .
. N . r b . p .
. B . . . . . .
White Ka4 in check by nc3 and ra7
Black kb6 in check by Qd6 and Nc4
Illegal due to both kings in check

wTot = 15, wPawns = 4, wProms = 3
bTot = 13, bPawns = 2, bProms = 3
pieceCnts = [1,1,3,4,2,1,2,3,3,2]
. . b . . . r .
. N . . r . . .
b . . . B . P B
p K N . . . . n
R p P . P . . R
. B . q . k . .
R . n r . q Q P
B . . . . b . .
White Kb5 in check by ba6
Black kf3 in check by Qg2
Illegal due to both kings in check

wTot = 13, wPawns = 0, wProms = 5
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,4,3,2,3,1,3,4,3,2]
r R . Q b . . .
. q . K . q . b
. . . n . r . p
B R . . n . Q .
Q . Q . b . . .
. . . r p . B .
. r . k . . N .
. . N R N . . q
White Kd7 in check by qb7 and be8 and ne5 and qf7
Black kd2 in check by Rd1 and Ba5
Illegal due to both kings in check

wTot = 16, wPawns = 2, wProms = 6
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,4,2,3,4,1,3,2,2,3]
n . . B B . . Q
Q . . N R . . n
q . . . . Q . q
. R r . b . . k
. . . . B P . N
q N . b N . n .
. . P . . . . p
Q K . r . . . .
White Kb1 in check by rd1
Black kh5 in check by Be8
Illegal due to both kings in check

wTot = 14, wPawns = 5, wProms = 2
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,1,3,3,1,1,3,2,4,1]
b . . . r q . .
b . . . . P r .
B . p . B R . .
b . . R . b q .
. . . . P P . P
. . . B N K . .
R . . . p P n Q
. . k . q . . .
wpx = 8-5-2 = 1    maxuwp = 2+5-2 = 5
bpx = 8-2-4 = 2    maxubp = 1+5-4 = 2
minopp = 5-5 = 2-2 = 0
White Kf3 not in check
Black kc1 not in check
Illegal due to white same colored bishops requiring extra promotion

wTot = 11, wPawns = 1, wProms = 4
bTot = 16, bPawns = 4, bProms = 4
pieceCnts = [1,4,0,2,3,1,3,3,2,3]
. b . B . r . N
. . r . Q . p .
. p . Q . K q .
. N . p . . . n
q k . . n Q . .
. q N . Q . r P
b . . . p . . n
. . . . . . . B
White Kf6 in check by pg7 and rf8 and nh5 and ne4
Black kb4 in check by Qd6
Illegal due to both kings in check

wTot = 13, wPawns = 0, wProms = 6
bTot = 14, bPawns = 3, bProms = 4
pieceCnts = [1,0,4,5,3,1,4,1,2,3]
. . N k n . q .
N . . . . B q .
. . . . . . n .
B . R . . . R .
. p . r . R . .
. p . . . b R .
p B B b N . . B
q q . . n . K .
wpx = 8-0-6 = 2    maxuwp = 1+5-6 = 0
bpx = 8-3-4 = 1    maxubp = 2+5-4 = 3
minopp = 0-0 = 3-3 = 0
White Kg1 not in check
Black kd8 in check by Ba5
Illegal due to 3 black pawns on and b files?!

wTot = 14, wPawns = 1, wProms = 5
bTot = 14, bPawns = 0, bProms = 6
pieceCnts = [1,3,3,4,2,1,1,6,4,2]
Q . B b . . n .
b r . n Q . . .
R . N . r . . r
. N . B . b . R
. k K R B . . .
. . r . . . . .
B . . . q P r Q
. b . . . . r .
White Kc4 in check by kb4
Black kb4 in check by Kc4
Illegal due to adjacent kings

wTot = 13, wPawns = 2, wProms = 3
bTot = 15, bPawns = 3, bProms = 4
pieceCnts = [1,3,2,3,2,1,2,2,4,3]
Q . q B R . . n
n b R . . . q .
b . . . . P P .
p . . . . k b Q
. . . . . . . p
. K . p . . . .
. b . . n N . Q
r . N B B r . .
wpx = 8-2-3 = 3    maxuwp = 1+4-3 = 2
bpx = 8-3-4 = 1    maxubp = 3+4-4 = 3
minopp = 2-2 = 3-3 = 0
White Kb3 not in check
Black kf5 not in check
Legal?!

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 0, bProms = 7
pieceCnts = [1,5,2,2,2,1,2,5,2,5]
n . . . . . . .
K . . . . . Q .
r . R R B . n b
r n . r . . P k
q . n . N . . .
. r Q . . Q . r
. B . . n . Q .
b Q . . N . . q
White Ka7 in check by ra6 and nb5
Black kh5 in check by Qf3
Illegal due to both kings in check

wTot = 15, wPawns = 3, wProms = 4
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,3,2,2,4,1,3,3,2,4]
Q . r . . N K .
. . . q n . b .
N . . P n . b .
P r . . P R N q
Q . . q . . R .
. . . . . N . .
. B . . n k B Q
. . . n r . . .
wpx = 8-3-4 = 1    maxuwp = 3+4-4 = 3
bpx = 8-0-5 = 3    maxubp = 1+4-5 = 0
minopp = 3-3 = 0-0 = 0
White Kg8 in check by ne7
Black kf2 not in check
Legal with white to move?!

wTot = 13, wPawns = 3, wProms = 2
bTot = 15, bPawns = 3, bProms = 5
pieceCnts = [1,2,3,2,2,1,3,1,3,4]
. q r q n R . .
b P p . . . n b
n . R B . q N .
. . P Q k P . .
. . . N . p . .
. . . K B . . n
p . . . . b . R
. . . . . . Q .
White Kd3 not in check
Black ke5 in check by Qd5 and Bd6 and Ng6
Illegal due to impossible double check on king

wTot = 12, wPawns = 3, wProms = 1
bTot = 16, bPawns = 3, bProms = 5
pieceCnts = [1,1,2,3,2,1,2,4,4,2]
N . . . q r . .
. . . N . . . .
. . B . K P p P
R k . P . . . q
b r Q . . . r b
p B . n r . . .
b . . . . n B p
. . . . . b R .
White Ke6 in check by qe8 and re3
Black kb5 in check by Ra5 and Qc4 and Bc6
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 1, bProms = 4
pieceCnts = [1,1,2,2,7,1,2,2,5,2]
R . . N . b . .
b . . N b . q .
. . B q . . . .
. . N p k Q b .
R . r N N N . .
r b . . P . n .
K P . . . . . N
. n B . . . . .
White Ka2 in check by ra3 and bb3
Black ke5 in check by Qe5 and Nd7
Illegal due to both kings in check

wTot = 14, wPawns = 3, wProms = 3
bTot = 15, bPawns = 4, bProms = 3
pieceCnts = [1,3,2,2,3,1,2,2,4,2]
. r . . . n . b
. . p b . r . p
. . k R q b p .
N . . . . Q K P
. . P . b . P .
. . N . B . . .
n . . . . R q p
. Q N Q . . B .
White Kg5 in check by bf6
Black kc6 in check by Rd6 and Na5
Illegal due to both kings in check

wTot = 14, wPawns = 2, wProms = 4
bTot = 14, bPawns = 2, bProms = 4
pieceCnts = [1,1,3,4,3,1,1,2,3,5]
R k B . . . . .
. K q . P N . p
. n . Q . n . .
. . r . . n . .
. . b N b . p .
. n . . . . . P
b B . . n B . .
N r . R . B . R
White Kb7 in check by kb8
Black kb8 in check by Kb7
Illegal due to adjacent kings

wTot = 14, wPawns = 3, wProms = 3
bTot = 15, bPawns = 3, bProms = 4
pieceCnts = [1,2,3,3,2,1,3,3,2,3]
q . . b q . N Q
p . . B . . . B
. . . . p . n .
. P n R P q . Q
. p K N . . k n
. . . . . . . .
r P r . b R . B
. . . R . r . .
White Kc4 in check by be2
Black kg4 in check by Qh5
Illegal due to both kings in check

wTot = 15, wPawns = 1, wProms = 6
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,5,3,3,2,1,1,4,3,4]
. . . Q . . . .
. Q . . Q . . R
. . . . r . . .
. . B k b n K .
r . . . n . N .
B . . . b n b R
. r P B q . . R
r Q n N . Q . .
White Kg5 in check by ne4 and nf3
Black kd5 in check by Qb7 and Qd8
Illegal due to both kings in check

wTot = 14, wPawns = 1, wProms = 5
bTot = 14, bPawns = 1, bProms = 5
pieceCnts = [1,3,2,4,3,1,1,5,3,3]
. Q . . B . Q B
K r b b . . R B
. . . . . . b .
P n . . . N . n
r . . . . . . N
. r r N . r k .
. . p B R . . .
. . Q . q . . n
White Ka7 in check by rb7 and nb5
Black kg3 in check by Nf5
Illegal due to both kings in check

wTot = 11, wPawns = 3, wProms = 2
bTot = 16, bPawns = 1, bProms = 7
pieceCnts = [1,3,1,1,2,1,3,4,3,4]
Q . Q q . . K .
q . n . P . . .
. P b . n . . .
. . . . . N . .
P . b B r . . .
. . Q . q . . N
k r n . p . R .
. . . r b n . r
wpx = 8-3-2 = 3    maxuwp = 0+5-2 = 3
bpx = 8-1-7 = 0    maxubp = 3+5-7 = 1
minopp = 3-3 = 1-1 = 0
White Kg8 in check by qd8
Black ka2 not in check
Illegal due to w made no captures while black needs 3 piece captures to get her pawns around white original a,b,e pawns

wTot = 13, wPawns = 2, wProms = 3
bTot = 15, bPawns = 3, bProms = 5
pieceCnts = [1,1,3,4,2,1,3,5,2,1]
. r . n . . N .
. k . . K B q .
. . . r b q p N
. R . . p B b .
. r . q R . . .
P . B Q r . R .
. p . . . B P r
. . . . . . . .
White Ke7 in check by qf6
Black kb7 in check by Rb5
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 3, bProms = 4
pieceCnts = [1,2,4,3,2,1,2,4,3,2]
r . b b . r . .
p . N . . b R .
. p . R . R . .
. . . . K n n .
Q q . . . q . .
B . . B p . r .
. R . N . . Q P
. . r B . . k .
White Ke5 in check by qf4
Black kg1 in check by Qg2
Illegal due to both kings in check

wTot = 16, wPawns = 3, wProms = 5
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,2,3,5,2,1,2,2,2,4]
R N . Q N . . .
P B . R . . P .
. . P b . B . B
. B n . . . . R
. k r . Q . q p
. . . . b . . n
. . . q . B n .
. . n . r K . .
wpx = 8-3-5 = 0    maxuwp = 4+4-5 = 3
bpx = 8-1-3 = 4    maxubp = 0+4-3 = 1
minopp = 3-3 = 1-1 = 0
White Kf1 in check by re1
Black kb4 not in check
Illegal due to black's same colored bishops requiring extra promotion

wTot = 13, wPawns = 0, wProms = 5
bTot = 15, bPawns = 3, bProms = 4
pieceCnts = [1,3,4,3,2,1,3,4,2,2]
. K r B b . R .
N . B n . R . .
q . . p . r . .
B Q . N p . . Q
. p . . . . . .
. Q . r k . . q
. . . . r . . .
. . . q n R R b
White Kb8 in check by rc8 and nd7
Black ke3 in check by Nd5
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 2, bProms = 5
pieceCnts = [1,3,3,3,2,1,3,2,3,4]
. . . Q q . r B
. . . . . N . .
R b N . R . . .
B . p n . b Q .
. b . . Q R . K
. q r p . . P .
. B . . k . . .
. n . n n q . .
wpx = 8-1-4 = 3    maxuwp = 1+4-4 = 1
bpx = 8-2-5 = 1    maxubp = 3+4-5 = 2
minopp = 1-1 = 2-2 = 0
White Kh4 not in check
Black ke2 in check by Qe5
Illegal due to white's same colored bishops requiring extra promotion

wTot = 14, wPawns = 2, wProms = 4
bTot = 13, bPawns = 2, bProms = 4
pieceCnts = [1,3,2,4,2,1,2,3,1,4]
. Q . R K . . .
. P n . r . . .
B r . . p . . k
. . n . . . . p
. . B r P . . N
. B N n b . B .
R Q . . . q Q .
. . . . q . . n
White Ke8 in check by nc7 and re7
Black kh6 not in check
Illegal due to impossible double check on king

wTot = 16, wPawns = 2, wProms = 6
bTot = 12, bPawns = 0, bProms = 4
pieceCnts = [1,2,2,6,3,1,1,3,2,5]
. r Q . . . . .
. P . . B . N .
n b . n . . r .
k R n r . . . .
. B . q . P . .
b . . . . . . R
. n Q B . N B .
n . . B . N K B
White Kg1 not in check
Black ka5 in check by Rb5 and Bb4
Illegal due to impossible double check on king

wTot = 14, wPawns = 0, wProms = 6
bTot = 14, bPawns = 1, bProms = 5
pieceCnts = [1,3,2,4,4,1,3,3,4,2]
N . . b . N . K
. . . . R b r .
R . . . . . Q B
. . . . . B . n
q p b . Q q . .
B B N . . . . .
Q N . k b . n .
. . r r . q . .
wpx = 8-0-6 = 2    maxuwp = 2+4-6 = 0
bpx = 8-1-5 = 2    maxubp = 2+4-5 = 1
minopp = 0-0 = 1-1 = 0
White Kh8 not in check
Black kd2 not in check
Legal?!

wTot = 11, wPawns = 0, wProms = 4
bTot = 15, bPawns = 1, bProms = 6
pieceCnts = [1,2,4,1,3,1,3,2,4,4]
B . . k R . . Q
n . N . . . . .
. r r . R . . Q
p . . . n N . R
n N . . . . . .
. b q K b . b .
. q . . q . . .
. n R . . . . b
White Kd3 in check by qc3 and qe2 and ne5
Black kd8 in check by Re8
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 4
bTot = 15, bPawns = 4, bProms = 3
pieceCnts = [1,3,2,3,3,1,2,3,2,3]
. R . B . B . n
. k . . . . P .
. . Q p . . n .
. . q . . N p .
. . . b n r Q B
K r b R N p r .
. p N . . . . .
. . . . q Q . .
White Ka3 in check by rb3 and qc5
Black kb7 in check by Rb8 and Qc6
Illegal due to both kings in check

wTot = 12, wPawns = 1, wProms = 3
bTot = 16, bPawns = 3, bProms = 5
pieceCnts = [1,2,3,2,3,1,3,2,4,3]
R . b . . . . Q
. . . b . K . k
n . . . N Q . .
. q N r . b . .
. P . . . p p .
. . p N n . B b
q . . . B . R R
n q . r . . . .
wpx = 8-1-3 = 4    maxuwp = 0+4-3 = 1
bpx = 8-3-5 = 0    maxubp = 4+4-5 = 3
minopp = 1-1 = 3-3 = 0
White Kf7 not in check
Black kh7 in check by Qh8
Illegal due to black's same colored bishops requiring extra promotion

wTot = 15, wPawns = 1, wProms = 7
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,4,2,6,1,1,1,2,4,3]
. . Q B n r . .
. b Q . b . b .
B . . . p . . B
. . . . . Q . R
. . r . . . K B
b P R . Q . B .
. . . . . N . .
. k q B n n . .
White Kg4 in check by rc4
Black kb1 in check by Qf5
Illegal due to both kings in check

wTot = 15, wPawns = 2, wProms = 5
bTot = 13, bPawns = 3, bProms = 2
pieceCnts = [1,2,3,2,5,1,1,3,2,3]
. . . . N . . .
. n . Q . . p r
. . . . P R . .
. r k n b N p .
. N R q . . N .
n P K . . . . .
b . p . . Q . B
B N r . . . R .
White Kc3 in check by qd4 and nd5
Black kc5 in check by Rc4
Illegal due to both kings in check

wTot = 14, wPawns = 0, wProms = 6
bTot = 14, bPawns = 2, bProms = 4
pieceCnts = [1,3,4,2,4,1,1,2,3,5]
b b r . . Q N .
R . . . B . q .
. R K N . . r p
. . . n . . n n
b R Q Q . . . n
. R . . . n . .
. p . . k B . .
N N . . . . . .
White Kc6 in check by ba8 and rc8 and ba4
Black ke2 in check by Qc4
Illegal due to both kings in check

wTot = 13, wPawns = 1, wProms = 5
bTot = 14, bPawns = 2, bProms = 5
pieceCnts = [1,4,1,2,4,1,6,2,2,1]
. . . N . q Q .
. . . p . N n q
. . b N . q p q
r . . B r Q . .
. . q q P Q . b
. . N . . . . k
. R . K . B Q .
. . . . . . . .
White Kd1 in check by qd4
Black kh2 in check by Qg1 and Qf4
Illegal due to both kings in check

wTot = 16, wPawns = 2, wProms = 6
bTot = 12, bPawns = 1, bProms = 3
pieceCnts = [1,5,4,2,2,1,2,2,3,3]
q . Q . . . Q .
. . . R r N . .
. R . b Q N . Q
. n . . . Q k R
r . . P . b . .
. B P . . . . .
K . p . R B . n
n . . . . b q .
White Ka2 in check by ra4
Black kg5 in check by Qf5 and Qh6 and Rh5 and Nf7 and Qg8
Illegal due to both kings in check

wTot = 15, wPawns = 1, wProms = 6
bTot = 13, bPawns = 0, bProms = 5
pieceCnts = [1,4,4,3,2,1,1,5,4,2]
. B r . . n b .
. . . . r Q b r
. b . q Q R . .
. . . . N . . .
. N r n . b B .
. . R . . R . Q
P . B . . R . k
. . . r . K . Q
White Kf1 in check by rd1
Black kh2 in check by Qh1 and Qh3 and Rf2
Illegal due to both kings in check

wTot = 14, wPawns = 2, wProms = 4
bTot = 14, bPawns = 1, bProms = 5
pieceCnts = [1,1,3,2,5,1,2,2,3,5]
. K . . . . . .
b . k . N . . r
p n q n Q . . .
. N . . . P . .
B . . . . . . r
R R . . P B . n
. N . . . n . N
R N . b . q b n
White Kb8 in check by kc7
Black kc7 in check by Kb8
Illegal due to adjacent kings

wTot = 14, wPawns = 2, wProms = 4
bTot = 14, bPawns = 1, bProms = 5
pieceCnts = [1,1,3,4,3,1,5,2,3,2]
. . . . . b . .
. Q . . . . . b
. k q . . . n .
. N . . B P . n
R . B . r r . .
q p P . N q q q
. . N B . . . R
. B R . . . K b
White Kg1 in check by qg3
Black kb6 in check by Qb7
Illegal due to both kings in check

wTot = 15, wPawns = 0, wProms = 8
bTot = 12, bPawns = 0, bProms = 4
pieceCnts = [1,1,7,1,5,1,3,2,4,2]
. R R N . . . .
R R b . R k . N
. n . . . q . .
. . N R . B n .
R . . . . . . b
. r . b q . . Q
. . . . N b . K
N . r . . q . .
White Kh2 in check by bc7
Black kf7 in check by Re7 and Nd8
Illegal due to both kings in check

wTot = 14, wPawns = 0, wProms = 6
bTot = 14, bPawns = 4, bProms = 2
pieceCnts = [1,1,3,3,6,1,1,2,3,3]
. b N . . . . .
N B . . . . . .
q . . . . . . p
. N n . k . p r
. r b R . . . R
Q p N b . p B n
. . . . N . n K
B . . N . R . .
wpx = 8-0-6 = 2    maxuwp = 2+4-6 = 0
bpx = 8-4-2 = 2    maxubp = 2+4-2 = 4
minopp = 0-0 = 4-4 = 0
White Kh2 not in check
Black ke5 in check by Bg3
Illegal due to black pawns on f,g,h files not supporting promotions by captures of pawns only

wTot = 13, wPawns = 3, wProms = 2
bTot = 15, bPawns = 1, bProms = 6
pieceCnts = [1,1,3,3,2,1,3,2,3,5]
. . Q r k . . .
. n n . . b . .
. N . . r . R P
. . . . B n n .
q q . . n p b .
R . B . . . . .
. . R . . P P b
q . K . B . . N
wpx = 8-3-2 = 3    maxuwp = 1+4-2 = 3
bpx = 8-1-6 = 1    maxubp = 3+4-6 = 1
minopp = 3-3 = 1-1 = 0
White Kc1 in check by qa1
Black kd8 not in check
Illegal due to white's same colored bishops requiring extra promotion

wTot = 13, wPawns = 2, wProms = 3
bTot = 15, bPawns = 0, bProms = 7
pieceCnts = [1,1,4,3,2,1,5,2,5,2]
. q Q . R . . .
R . . . . b . B
b . k q P . . q
. . . B r r q .
B . . . . b . .
n K . b R q n .
b . . . . P . .
. N N . . . . R
White Kb3 in check by ba2 and qb8
Black kc6 in check by Qc8 and Ba4 and Bd5
Illegal due to both kings in check

In total 4 legal with either side to move and 8 legal with one side to move,
for 8% sample position legality and estimated number of positions ~7E44.

Top reasons for illegality (later ones conditional on absence of earlier ones):
53x Illegal due to both kings in check
11x Illegal due to impossible double check on king
10x Illegal due to adjacent kings
 7x Illegal due to same colored bishops requiring extra promotion
(the above ~80% of illegalities should be automatically recognized, leaving roughly half of remaining positions (half)legal)
 1x Illegal because wProms=6 requires missing pawn files to come in 3 adjacent pairs
 1x Illegal due to Ba1 trapped by Pb2
 1x Illegal due to no white pieces captured to double black c pawns
 1x Illegal due to doubled h pawn requiring extra capture
 1x Illegal due to 3 black pawns on and b files?!
 1x Illegal due to w made no captures while black needs 3 piece captures to get her pawns around white original a,b,e pawns
 1x Illegal due to black pawns on f,g,h files not supporting promotions by captures of pawns only