Here is the problem with your solution for mate-in-3:
If black moves 1... Bb7, he will not be forced to move his bishop next turn (he will have 2... Ka8) and so your mate is extended to four moves.
I believe that only the solution given by Chessmaster is correct.
White to move, Mate in 3!
Hi all,
Found this little puzzle in my Chessmaster 10 game (Leon-Martin, 1930)- now my solution is a little different from what's given and I'll explain it below, then copy and paste the game's solution. If you can tell me whether or not my solution is OK that would be greatly appreciated.
Mine:
Promote either pawn to a queen. Black must move bishop to d8 or b8 to prevent mate in 2. Now under no condition can I take this bishop, else black is stalemated. Knowing this, I simply move the queen left or white (just kill a turn), since black will be forced to move the bishop next turn, as it his only free piece. Upon doing so he will allow ra8++, which wins the mate in 3.
Game's:
"If White promotes a pawn immediately by 1 e8Q or 1 g8Q, then Black replies 1...Bb8, and White cannot take the bishop because of stalemate, so there is no mate in two. The correct plan is to arrange for the rook to be on the other side of the queen, so that ...Bb8 is no longer an effective defense. However, 1 Rg8? (1 Rf8? is also met by 1...Bd6) fails to 1...Bd6 2 e8Q Bf8, blocking the back rank.
The rook must go to the very end, so as to give White a choice of promotions. White doesn't threaten anything, because 2 e8Q and 2 g8Q would be met by ...Bd8, but Black's bishop cannot stay on c7. After 1...Bd6 White plays 2 g8Q, intending Qa8 mate, while if the bishop moves to any other square on the b8-h2 diagonal, White forces mate by 2 e8Q.
1...Bd8. The best defense.
2 e8Q? and 2 g8Q? are met by 2...Kb8, while 2 exd8Q? is stalemate.
2 exd8B! White avoids stalemate by underpromoting. Once again there is no threat, but Black's king is forced to move onto the dangerous back rank. 2...Kb8 3 Bxb6 mate."