Mate in 5 — Problem #1998421
Black to move — find the mate
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9
8
7
6
5
4
3
2
1
一
二
三
四
五
六
七
八
九
☗
Show solution
▲５三歩成 △同 玉 ▲６三馬 △４二玉 ▲４一銀成
Why this move works
The answer is ▲５三歩成 △同玉 ▲６三馬 △４二玉 ▲４一銀成. Promote a pawn with ▲５三歩成 and let the king take it (△同玉) to pull it to 5三, drive it back with ▲６三馬, and mate with ▲４一銀成.
Sacrificing the promoted pawn lures the king out, and the horse and promoted silver — together with the king’s own pieces (knight 3一, gold 3二, pawn 4三) — seal every flight square. A small sacrifice setting up a big finish.