Bonce

Ow! An apple fell on my bonce.

Source: tatoeba (10068546)

Bonces, or very large stone marbles, made chiefly in Holland.

Source: wiktionary

BONCE ABOUT is played with a big kind of marbles, called "bonces." The game does not require much skill. The first player puts down his bonce, and the second aims at it from a given distance. If he hits the bonce of the first player with his own, he wins a marble; if not, the first player aims at the bonce of the second, from the place where his own rests. Each time the bonces strike together, a marble is lost and won. […] The Dutch marbles of grey stone, sometimes stained with various colours, are the honest workable marbles for "shoot in the ring," and similar games.

Source: wiktionary

Bonce is played with very large marbles. One boy pitches his bonce, and another tries to strike it, each throwing by turns: if the bonce be struck, its owner pays a forfeit of one or more marbles, as agreed on.

Source: wiktionary