Now that I have your complete attention…
This innocent post concerns 変体仮名 (hentai gana), which are alternative, obsolete hiragana characters. (“Hiragana” is one Japanese “alphabet” or “syllabary,” the other being “katakana”.)
“Hentai”（変体）means “variant” or “abnormality.” (“Hentai” also means “pervert” but is written with different kanji: 変態).
In modern Japanese, 46 hiragana letters are taught and used. Yet occasionally you may encounter non-standard hiragana ゐ (wi) ゑ (we)—that are obsolete and are now substituted with い and え.
Both the hiragana and katakana syllabaries were created by simplifying kanji 漢字, characters originating from China. In short, kanji were selectively applied phonetically to represent Japanese sounds. These characters were later simplified, in a cursive style, creating hiragana, and in a square style, producing katakana.
Here are some examples:
(kanji on the left, hiragana on the right)
安→あ 以→い 宇→う 衣→え 於→お 加→か
The relationship becomes clearer if you write with the traditional brush and ink.
This is an article commemorating the 100th birthday of a woman, but most people today would be unable to read her name. The characters used for her given name are hentai gana.
Prior to 1900, hundreds of hiragana were taught, sometimes five or six alternatives for one sound, all derived from various kanji. The modern hiragana for the sound “to” is と, which is derived from the kanji 止 and for “mi” み the hiragana is a simplified version of 美. In the photo, the “to” used in the woman’s name comes from 登 and the “mi” is an obsolete alternative also derived from the kanji 美.
(This link has a chart with over 500 hentai gana—imagine learning all these at school!)
Such variants enhanced the aesthetics of writing. Why use the same letter twice in one sentence and appear repetitive? Similarly, in English, writers often avoid repetition of words out of stylistic preference.
Wandering around Japan, you can occasionally spot hentai gana used in shop signage—funky, in a retro way. You’ll surprise all your friends if you can identify the writing as hentai gana, and impress them even more if you can read them.
The photos above and below are examples I found in Odawara.
Once you know what to look for, you may encounter perverted characters around town yourself. Happy hunting!