[thras]

The mnemonic method being referred to is aimed as specifically learning written Japanese. It is not about learning words. It's about learning kanji.

The problem is that Japanese has the most complicated written language in the world. It has two alphabets and a set of many thousands of symbols (kanji) borrowed from Chinese. Learning spoken Japanese is an entirely different undertaking than learning written Japanese.

You can be completely fluent in Japanese and still not be able to read a newspaper (this may actually be more common than not).

[pradocchia]

I learned Kanji (or Hanzi, as it were) by rote practice and careful attention to the calligraphy of each stroke. It turns out each stroke has a rhythm, and the sequence of strokes have a composite rhythm unique to the character.

Rhythm is an important mnemonic aid. The Homeric epics are poems because poetry has meter and rhyme, and people needed that to remember the whole thing. Same thing with Kanji.