Checkmate on 5x5x5: Starting with King and 3 Rooks versus a lone King, the White King can make its way onto the central cell (Cc3) without much difficulty. The Black King is now restricted to the 98 cells on the six faces of the playing area. It should be possible to then force a position with the lone King trapped on one face, for example level 'A'. The following (Zillions tested) checkmate in 14 moves looks fairly convincing.
* * *
(Black King Ab2)
(White King Cc3)
(White Rook Ba5)
(White Rook Be5)
(White Rook Be1)
1. Rook Be1 - Ba1
1. King Ab2 - Ac2
2. Rook Be5 - Ae5
2. King Ac2 - Ad3
3. Rook Ba5 - Be5
3. King Ad3 - Ac2
4. Rook Ae5 - Ab5
4. King Ac2 - Ac3
5. Rook Ba1 - Be1
5. King Ac3 - Ac4
6. Rook Ab5 - Ab1
6. King Ac4 - Ac3
7. Rook Be1 - Ae1
7. King Ac3 - Ac4
8. Rook Ae1 - Ad1
8. King Ac4 - Ac5
9. Rook Ad1 - Ad3
9. King Ac5 - Ac4
10. Rook Ab1 - Ab3
10. King Ac4 - Ac5
11. King Cc3 - Cc4
11. King Ac5 - Ac4
12. Rook Be5 - Be2
12. King Ac4 - Ac5
13. Rook Be2 - Ae2
13. King Ac5 - Ac4
14. Rook Ae2 - Ac2
* * *
Checkmate on 6x6x6: If we somehow reached the position given above, can White still force a similar checkmate? Note that the Black King is trapped inside a 5x5 area on level 'A' and should not be allowed to escape.
Checkmate on 5x5x5: Starting with King and 3 Rooks versus a lone King, the White King can make its way onto the central cell (Cc3) without much difficulty. The Black King is now restricted to the 98 cells on the six faces of the playing area. It should be possible to then force a position with the lone King trapped on one face, for example level 'A'. The following (Zillions tested) checkmate in 14 moves looks fairly convincing.
Checkmate on 6x6x6: If we somehow reached the position given above, can White still force a similar checkmate? Note that the Black King is trapped inside a 5x5 area on level 'A' and should not be allowed to escape.