Every Chinese character is under one radical 部首 bùshǒu，which is the main category of a word. It gives you a clue about a word’s meaning. For examples, words under the radical 貝, which means shell, usually has something to do with money or treasure, because for a period of time, shells used to be the currency in ancient China.

When I was in elementary school we had Bushou competitions in which if you recognized the most Bushous, you win. The difficult part of the competition is that sometimes, a word can have several components that each part can possibly be the radical, such as the word old “舊”。

舊 has the grass radical “艸” on top, bird radical “隹” in the center, and the mortar radical “臼” on the bottom. At first glance, it is hard to tell which one is the true radical. If you know the meaning of the word, it might help you decide, since neither grass nor bird can directly be associated with the meaning “old”.  Therefore the image of a dusty mortar might be the closest thing to a character that means “old”.

It turns out that 舊 is indeed under the mortar radical “臼”.

I recommend this Bushou game to more advanced students, enjoy!