ILLEGAL: !ffp g7-g5 on turn 15:
There was no !ffp on g7. The piece on g7 is a app.
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For diagnostic purposes, here is the full movelist:
1. !AAK b1-c8 
1... !aak b8-a1 
2. ~BT c1-b1 
2... !aak a1-h2 
3. K h1-h2 
3... c e8-c8 
4. pass 
4... pass 
5. P g2-g3 
5... p b7-b6 
6. P d2-d4 
6... _jj_tn f8-g5 //Check!
7. P f2-f4 
7... _jj_tn g5-d4 //g5-e3-d4
8. P b2-b3 
8... p h7-h5;S18-h7;A18-f8 
9. _JJ_FN A1-h1; S1-d2; d1-d3 
9... _jj_tn d4-f4 //Check!
10. K h2-g2 
10... p g7-g6 
11. P e2-e3 
11... _jj_tn f4-d6 
12. _JJ_FN h1-f3 
12... _jj_fn f8-h6;B18-f8;T18-g7 
13. _JJ_TN f1-h3; B1-h1; T1-h2 
13... .1ef a8-c6 
14. ~HF~ d3-e2 
14... p e7-e6 
15. P c2-c4 
15... !ffp g7-g5 
16. _JJ_FN f3-f2 
16... p f7-f5 
17. C e1-d1 
17... _jj_tn d6-f6 
18. ~BT b1-c2 
18... !i f8-f7;C18-f8 
19. !C C1-f1; d2-d4 
19... ~hf~ d8-e7 
20. ~BT c2-d3 
20... c c8-e8;U18-b7 
21. QP U1-a1; e2-c2 
21... _jj_tn f6-f2 //f6-h4-f2
22. X U3-e2; g2-f2 
22... resign
In case there is a bug in the code, the settings file can be edited at /play/pbm/play.php?game=UC-170-13&settings=Mirror&submit=Edit