Test your chess: Reitstein problem 228

White to play and win

C Wolpe v P Kunne 1985

Solution

The first moves are obvious: 1 Re4! has to be played, and if 1…fe, 2 Qe4+. Then it depends on where black moves his king to. First, if 1…Bd5, 2 ce fe[] 3 Qe4+ with essentially the same problem: it is white's c3 bishop which matters most. I will take 1..fe as the main line.

Then 2 Qe4+ and whether black plays 2…Kh8 or 2…Kg7 ( 2…Kg8?? 3 Qg6+ drops the bishop) white plays 3 Rf6! with decisive entry.

If instead black plays 1…Bd5 then after 2 cd the game can either proceed the same way: the rook enters, and h6 drops off, or, white has a new line: exchange rooks on f8 and (after Rf8 Rf8) play Bb4, and simplify into a own queen and pawn ending, with two extra passed central pawns.

The Bb4 line was shown to me by Stockfish: I just played on the king side, not the whole board. It puzzled me why after Rf8 it strongly preferred Rdf8 to Qe7f8: the reason turns out to be that from e7, the queen looks along the seventh rank, and so can if necessary play Qh7, stopping Qg6+ and Qh8+ depending on the line played. From f8, the queen csn't stop a white queen entry.

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