Test your chess: Reitstein problem 60

K O'Sullivan v G Boulle 1981

Solution

I took longer than I should on this one, getting distracted by false ideas such as sacing the queen. Once I refocused, and became calmer, it was straightforward. Examine all biffs means that 1 Nf6+ has to be examined, when 1…Kh8 is forced, since 1…Bf6 loses a piece (since the Bg7 is tied to defending h6) to 2 Qh6+ and 3 Rf6, 1-0. So, (1..Kh8) 2 Qh4 and as soon as you see that 2…Nf5 is met by 3 Rf5! Bf5 4 Bh6, the rest is easy: 2…Ng8 3 Ng8 and 4 Bh6 similarly wins a piece.