Over the years, winks have been made of bone, vegetable ivory, clay, celluloid, wood, various plastics, ivory (rarely), and even metal. Winks have been round discs (mostly), rings (quoits), square, horseshoe-shaped, and more. Squidgers are typically round discs, but have also been square, pointed, tennis-racket-shaped, and golf-club-shaped. And more.

The key criteria (technically speaking) for declaring a game to be a tiddlywinks game is that the squidger is used by a human and is flicked across a flat wink with a stroke that has a combined downward and horizontal component. This leaves out games where a shooter is used with a mainly horizontal stroke, such as in marbles, and omits games where the squidger is directly attached to the wink and games in which winks are catapulted using a lever.

Though this be madness, yet there is method in ’t. [William Shakespeare, Hamlet, Act II, ii, 211.]

The two key ingredients of tiddlywinks rules that were in effect in 1890, for most varieties thereafter, and remain intact today are:

• The offensive shot involves shooting a wink toward a target and having the wink land on, in, or through the target. In modern terms, when a wink lands inside the targeted cup, it is deemed potted and earns more points.
• The defensive shot entails shooting a wink so it lands on top of an opponent wink. The opponent wink cannot be played by the opponent while it is covered. In modern parlance, the opponent wink is said to be squopped. In rules from the 1890s, it was not proper to intentionally cover an opponent’s wink with yours, but if it did happen, perhaps accidentally, the opponent still was not allowed to shoot the wink.