Second key · The Horned Beast Bars the Way

What the solver found: an exact audit of the classical manuals

7 moves

The Horned Beast Bars the Way (角端阻道) — Deep as the Sea (渊深海阔, 1808), no. 71 The book opens Rxd8+ and mates in 4. So does Rb10+: the key is not unique. The mainline is the book’s solution; a branch, where there is one, is what the solver found. Record from dpxq.com.