Four

Reading: SHI, yon, yo-

Strokes: 5

Etymology: Four was once shown by four horizontal strokes.

Interestingly, this character originally meant breath (see breathe emerging from mouth 口).

四 became a phonetic substitute, and also it resembles an image of a closed fist (if close your left eye and tilt your head).

Mnemonic: FOUR FINGERS IN CLENCHED FIST

Combinations:

四月 (shigatsu) April

四日 (yokka) the fourth day 

四回 (yonkai) four times

(based upon Henshall, 1998)