# Bow or lazy checkmate?

Suppose that both players cooperate, find the shortest, in terms of number of moves, black checkmate such that the game is valid and white pieces never go on rows 4 to 8.

e.g. 1. e3 is valid while 1. e4 is not (a pawn went to row 4).

We search for a black checkmate, i.e. whites must win!

• So black checkmate = white wins? Nov 11, 2022 at 8:06
• @Stevo yes, sort of, because whites can also win if black resigns, which is not wanted here!
– JKHA
Nov 11, 2022 at 12:38

4.5 is doable, see the checkmate position below.

1. e3 e6
2. b3 Ke7
3. Nh3 Kf6
4. Bb2+ Kf5
5. Bd3#

This seems to fit the criteria as far as I understand it (with white winning):

I can get it into 6.5 moves:

Why optimal path?

Not neccassary optimal though. 1 move mate, 2 move mate, and 3 move mate are all not going to work. I don't know about 4,5 or 6 move mates, however in this scenario the king has to walk to the other side of the board