<div>b) 1.e3? the e-pawn is missing!</div><div>1.Kxh4! Kh8 2.f8=Q+ Kh7 3.Qf7 Kh8 4.Qxg6 Kg8 5.Qe8+ Kh7 6.Qh5+! Kg8 7.g6 Kf8 8.Qe2 Kg8 9.Qe8#</div><div><br /></div>Each solution begins with a move up one square. More importantly, the twins have the switchback of the promoted P to f7, the different pure round trips over three moves with the intervening white g-pawn, (a) Qf7-g6-e8-(wPg6+)-f7 and (b) Qe8-h5-(wPg6)-e2-e8, the switchback (a)&amp;(b) bKh7-h8-h7, the pure round trip (a)&amp;(b) bKh7-h8-g8-h7 and finally the various switchbacks, (a) bKh6-h5-h6 and (b) bKg8-f8-g8. They are therefore a good twin pair. Kindergarten problem.<div>You can find the complete animation mode at PDB:</div><div>https://pdb.dieschwalbe.de/P1414038.</div><br />