Okay a. was too easy and it's even better ifBlack has to checkmate White because then there will be no waiting move:
1. e3 Nc6 2. g3 Ne5 3. Ne3 Nf3 mate
White would need 4 moves to mate like that.

Part b. is more difficult though, but should be possible also 🙂

Originally posted by ark13 Well, he moved some pawns, so I'm guessing it's not a valid solution.

The solution with the pawn moves is for part a.
For part b. I found 9 moves.
1. Nf3 Nf6 2. Nh4 Nh5 3. Nf5 Nc6 4. Nxe7 Nb8 5, Nf5 Nc6 6. Nxg7+ Nxg7 7. Nc3 Ne7 8. Nd5 Ngf5 9. Nf6 mate

Originally posted by crazyblue The solution with the pawn moves is for part a.
For part b. I found 9 moves.
1. Nf3 Nf6 2. Nh4 Nh5 3. Nf5 Nc6 4. Nxe7 Nb8 5, Nf5 Nc6 6. Nxg7+ Nxg7 7. Nc3 Ne7 8. Nd5 Ngf5 9. Nf6 mate

can you think of similar one like this? i was thinking of "both may only move knights and bishops and the mate has to be with bishop" but it turned out to be too easy.

Originally posted by crazyblue Very nice. Looks like the Knight Award goes to Thud unless someone can find a solution in 5 🙂

There is no way to improve that 😉 Four moves to capture the queen and two to mate 😉
Anyway, an interesting question is if you require both side to alternate moves with certain pieces what is the shortest mate? For instance, both sides move pawn, then knight, then bishop, then again pawn, knight, followed by bishop, and so on.

Sounds fun. I guess in your example it's too easy though. White plays 1. e4 2. Nf3 3. Bc4 4. any pawn 5. Ng5 6. Bxf7 mate
Black can play anything on the queenswing in the meantime 🙂

Originally posted by crazyblue can you think of similar one like this? i was thinking of "both may only move knights and bishops and the mate has to be with bishop" but it turned out to be too easy.

Have you tried BigDogg's A game ends with 6.BxRc4#. Give the complete gamescore.?

Originally posted by crazyblue The solution with the pawn moves is for part a.
For part b. I found 9 moves.
1. Nf3 Nf6 2. Nh4 Nh5 3. Nf5 Nc6 4. Nxe7 Nb8 5, Nf5 Nc6 6. Nxg7+ Nxg7 7. Nc3 Ne7 8. Nd5 Ngf5 9. Nf6 mate

Yeah, but you started with white playing e3. It's white that's the one who has to only move knights, right? 😕 I'm sure I'm confused.