Red's horse sacrifices on i1 to force the black rook into a vulnerable spot, allowing the king to infiltrate and deliver checkmate.
The position features only a red king and horse against a black king, cannon, advisor and rook. The cannon and advisor are stuck on the far side of the board, unable to defend the i‑file. By playing H×i1, Red forces the black rook to recapture, exposing the i‑file. The red king then steps onto d0 (or e0) and begins a king‑and‑horse chase that drives the black king into the corner of its palace, culminating in a forced mate. The lesson is that in minimal‑material endgames a well‑timed piece sacrifice that creates a structural weakness, combined with active king play, can overturn a seemingly solid defense.