The first thing to notice is that White is a knight and a pawn ahead, but his bishop is attacked, and Black also has designs on the immobile b-pawn with Bd2. The simple 1. Nf3+ Nxf3 2. Bxf3 leads to nothing after 2 . . . Bd2: a glimmer of hope is offered by the prospect of a knight fork on c6, but 3. Na7 Bxb4 4. Nc6+ Kf4 still leaves no winning chances.
1. Ng4+ is another blind alley; after 1 . . . Kf5 2. Bh3 or 1 . . . Kf4 2. Nf2 Nxg2 3. Nd3+ Ke3 4. Nxc1 White may be winning, but 1 . . . Kf4 2. Nf2 Ke3] 3. Nd1+ Kd2 leads again to a draw.
The idea in the first variation of Na7 and Nc6+ does, however, provide a framework for a winning attempt: White moves his bishop somewhere safe, then meets Bd2 with Na7, either retaining his all- important pawn, or winning with Nc6+ after Bxb4. But when we get down to details, finding a safe place for the bishop is not so easy.
1. Bc6? has the big drawback of taking c6 away from the knight. 1. Bc6 Bd2 2. Ng4+ again offers false hope with 2 . . . Kf4 3. Nf2 leading to a fork on d3, but 2 . . . Kf5] 3. Bd7+ Kg5 gives a safe draw.
1. Bf3? and 1. Bh3? are too close to the Black king: after 1 . . . Bd2 2. Na7 Bxb4 3. Nc6+ Kf4 4. Nxb4 Black has 4 . . . Nxf3 in the first case and 4 . . . Kg3 in the second.
1. Bf1? seems to be out of range, but also fails since 1 . . . Bd2 2. Na7 Bxb4 3. Nc6+ Kf4 4. Nxb4 Kg3 now leaves the knight no way to escape.
Only one move remains to be looked at, so if 1. Bh1 doesn't work, we are in trouble. After 1. Bh1 Bd2 2. Na7 everything looks fine. If White is allowed to play 3. b5, he will win with his extra material, while after 2 . . . Bxb4 3. Nc6+ Kf4 4. Nxb4 Kg3 5. Nf1+ Kf2 6. Nd2 White retains his extra piece. But Black has one last trick. After 6 . . . Ng2, the bishop is stifled in the corner. Black threatens Kg1, forcing its exchange, which would leave White with the drawn ending of two knights against king.
The solution needs a final flourish, which is provided by 7. Nd3+ Kg1 (7 . . . Kg3 loses to 8. Nf1+ Kf3 9. Ne1+) 8. Nf3+] Kxh1 9. Nf2 mate. Two knights do not win against lone king, but they may, in the hands of an ingenious composer, beat king and knight.
The key to solving it is to recognise the early blind alleys, then not to give up after 6 . . . Ng2.
12 of the 18 finalists, incidentally, succeeded in finding the solution, with solving times ranging from 6 minutes to the full 35.Reuse content