Green’s Dictionary of Slang

(bingo) the number six or 26.

1943		M. Harrison Reported Safe Arrival 85: ‘Twenty-six’ is more often ‘Chopping Sticks’.
1960		J. Franklyn Dict. of Rhy. Sl. 50/2: Chop sticksSix.
1971		‘Jack Jones’ Rhyming Cockney Sl.
1981		P. Wright Cockney Dialect and Sl. 109: 6 = Tom Mix, (more modern) choppin’ sticks or chopstiks.
1992		R. Puxley Cockney Rabbit.
2002		B. Kirkpatrick Wicked Cockney Rhy. Sl. 20: chopping sticks six.