dt gk

[rockfordill]

Just one clue to get

21ac Game in which alternate players take one or more objects from one of a number of piles and try not to have the last object (3) N?M

I don't think that I have ever played this game !

[tyrepill]

Nim

[lizwhiz1]

nim - game in which matchsticks are arranged in rows and players alternately remove one or more of them; in some versions the object is to take the last remaining matchstick on the table and in other versions the object is to avoid taking the last remaining matchstick on the table
table game - a game that is played on a table

[rockfordill]

Many thanks tyrepill and lizwhiz (again) - now I can get down to the serious �500 crossword