Memorising kanji readings is one of the biggest hurdles when learning Japanese. Many kanji have two or more readings that need to be learned in addition to their meanings. By learning the phonetic components, this task can be made a lot easier. If you don’t like rote learning, you will love the phonetic components.
Most people know about the radicals, the part of a kanji character that indicates its meaning or meaning category. For example, the radical in forest 森 is tree 木. The phonetics are the other side of the same coin, but instead of giving a hint to the meaning, they give a hint to the ON reading.
For example, the phonetic SEI 青 appears in the characters for clear 清, ask and spirit 精, and they all have an ON reading of SEI.
The Kanji Code provides a list of 150 phonetic components, with the sound they represent and example words that use that reading. By memorising these phonetic components, reading kanji becomes a systematic process rather than a stab in the dark.
The Kanji Code also contains an easy to read explanation of the keisei or form-sound kanji characters (形声文字), which make up 80% of the Joyo or daily use kanji. These characters contain a radical that indicates the meaning, and a phonetic component that indicates the reading.