日

It is a pictogram originally representing the sun. It is one of the most frequently cited examples showing the evolution of Chinese characters from pictograms. Its origin is roughly the shape of a circle with a dot in the middle (⊙). Initially, the sun was depicted exactly as a circle or concentric circles engraved like on a tortoise shell, but as civilization advanced and the number of characters increased, the number of lines in the sun symbol gradually reduced. Eventually, the symbol was abstracted and simplified, changing from a circle to a square.

Another theory says that the middle line is not a dot but represents the horizon, and the outer shape shows the sun’s path over a day.

The character 曰 (meaning "to say") looks similar to 日. Originally, 日 (sun) and 曰 (to say) were distinct, but since the clerical script period, their shapes became very similar.

They can be distinguished in two main ways:

1. By aspect ratio — 日 is taller vertically, whereas 曰 is wider horizontally.

2. By whether the middle horizontal stroke touches the enclosing stroke — in 日 it does touch, in 曰 it does not.

However, this depends on the font style and should not be the sole basis for distinction.