二
に · ni · JLPT N5 · noun
two
✌️ 二 = two strokes for two; ni sounds like knee, and you have two knees
The character is simply two horizontal lines, one per unit counted, just as 一 is one line and 三 is three. For the sound, ni matches the English word knee, and knees come in a pair, so the reading itself points back to two.
二 — two horizontal strokes 一 + 一
二 is an indicative character showing the number two with two simple horizontal lines, parallel to 一 (one) and 三 (three). The form has been stable since oracle bone script. It directly represents the concept of 'two' rather than depicting any physical object.