Check = Mate

1. If the player who checks first is the winner, show how White can win in 5 moves from the initial position.
2. Suppose white is allowed to move only his knights. Can he still win (= be the first player to check the opponent's king)? in how many moves?

no

this is called "one check chess", it was in vogue about 80 years ago around New York City until Frank Marshall pointed out that 1. Knight-c3 wins and cannot be stopped. It checks in 3 moves.

Wrong answer. White cannot force a check in 3 moves.

well. I've looked at a board and can't figure out how to stop it, please enlighten me, what does black do to prevent a check in three?

I think e6 prevents check in 3

Originally posted by idioms
I think e6 prevents check in 3

Originally posted by GreatSantini
nope, knight-b5 and it's check on the move

Originally posted by idioms
Ke7