Responding to my Monday post about tadpoles and snails, Thomas asks: "So what's the difference between the two words for frog: kaeru and kawazu?" The common answer is that kawazu is the "old word" that got replaced by the "new word" kaeru, but this is a misconception. It's really just another case of semantic overlap combined with poetic versus everyday register.

It's true that there are no kaeru as such in the Manyōshū -- all the frogs that appear as frogs are kawazu (/kahadu/, at the time). But this is not because the word kaeru had yet to be invented. How do we know this? Because it appears inside other words -- specifically, kaerude (literally "frog hand"), which became the modern word kaerude, maple. Check out this poem by Lady TAMURA (田村大嬢) to her younger sister:

wa ga yado ni/ momitu kaherude/ miru goto ni/ imo wo kaketutu/ kohinu hi ha nasi

吾屋戸尓/ 黄變蝦手/ 毎見/ 妹乎懸管/ 不戀日者無

Every time I see the maple leaves turn in my garden, that day does not exist, O sister, which does not find me longing for your company

Some versions have momituru kahede or some minor variation, but the use of the kanji 蝦, which means "toad" or "big frog", to get the kae(ru) sound is constant. So, the word was there. Why didn't they use it?

One reason was that kaeru was a general word, while the original meaning of kawazu seems to have specifically been "kajika frog". The kajika frog is so called because it lives in rivers (ka(wa)) and has a haunting call like a deer (shika), making it ideal for use in poetry. Virtually all of the Manyōshū poems that include a kawazu specifically refer to its call.

Maybe for this reason, kawazu also seems to have been the preferred word in poetry for frogs in general. There is a word for this in Japanese aesthetics: kago (歌語, "poetry word"). Another good example is references to cranes: the word tsuru is plenty old (some say it came over direct from the continent), but most early poems used the word tazu (たづ) instead. That was the kago.

So maybe kawazu originally meant "kajika frog" in particular, but it didn't take long before it just meant "frog [+poetic]" in general. Meanwhile, kaeru was a perfectly healthy synonym meaning "frog [-poetic]".

Eventually, poetry would be modernized in such a way that people felt quite comfortable using the word kaeru, which left kawazu stranded, gradually shifting towards meaning simply "frog [+archaic]". Kaeru, on the other hand, became simply "frog" (unmarked).

Kawazu would probably have been forgotten by all but the specialists by now (much like tazu) if it weren't for one thing: the Dark Side of the Moon of traditional Japanese poetry, that one haikai by Bashō that everyone knows...

古池や かはづ飛び込む 水の音

Furuike ya/ Kawazu tobikomu/ mizu no oto

Old pond/ Frog jumps in/ Sound of water

Bonus fact: Bashō was actually consciously playing with the kawazu tradition here by attributing the sound to the water rather than the frog. The frog's implied silence, after centuries of naku kawazu, is a crucial part of the stillness that allows the sound of water to make its impact.