Sidenote: Kanji classes

Around 100 CE, Chinese scholar Xu Shen categorized Chinese characters into six classes (六書 in Chinese and Japanese).1 These classes aren't defined by strict rules nor are they mutually exclusive categories, but they serve as a useful framework for understanding how kanji works. Of the six classes, four are the most practical for learning kanji: shoukeimoji, shijimoji, kaiimoji, and keiseimoji.

You don't need to memorize these classifications though. What matters is knowing that kanji can be generally sorted into these groups. Beginners are often taught that kanji look like what they represent, but that only describes one class of kanji—that class not even making up the majority of modern kanji. Understanding these classifications helps to know why some kanji look the way they do and how they work.

Shoukeimoji (象形文字)

Shoukeimoji are kanji that visually depict the object they represent: pictograms. Some examples are 目, 木, and 人. If you use your imagination, 目 looks like an eye, 木 looks like a tree, and 人 looks like a person.

Shijimoji (指事文字)

Shijimoji are kanji that non-arbitrarily depict abstract ideas: ideograms. Some examples are numbers like 一, 二, and 三. Similarly, up, down, and middle: 上, 下, and 中, respectively.

Kaiimoji (会意文字)

Kaiimoji are kanji that are made up of meaningful components, and these components often tell a story: compound ideographs. The example from Strategy #1 is an example of this. Some others are 森 and 休, the characters meaning forest and rest, respectively: three trees (木) make a forest, a person (亻) rests next to a tree (木).

Keiseimoji (形声文字)

Keiseimoji are kanji that are made up of a phonetic component that indicates its onyomi reading and a semantic component that indicates its meaning.

An example of this is with the phonetic component 里 (リ).

All of these kanji share the exact same onyomi reading, but the kunyomi reading and meanings differ.

When looking up the meanings of the semantic components, we learn that 王 indicates that 理 relates to kings or jade, 犭indicates that 狸 relates to animals, and 魚 indicates that 鯉 relates to fish.

While the phonetic component of keiseimoji informs its onyomi reading, shared phonetic components do not always produce the same onyomi readings, so be careful—don't assume that every kanji sharing a component has the same onyomi reading before consulting a dictionary. Similarly, semantic components aren't always concrete indicators of a kanji's meaning due to meanings changing over time (like in the case of 理).

1. Reference: Omniglot's webpage, "Types of Chinese characters."