What role do the Siddham characters have in Japanese?


The bonji, 梵字, are somewhat common. Are the only used as germ letters in
Japanese, as has been explained to me, or are they used to form words and
other higher concepts? Is this a living language process?

On a popular level, they are used as germ letters on gravestones and t-shirts
from what I understand. Is there more extensive use?




You can read about the history of 梵字
[here](https://en.wikipedia.org/wiki/Siddha%E1%B9%83_script). Briefly, this
script is just one of the old scripts used in India, but Japanese Buddhist
monks admired it as a sacred script because many Buddhist scriptures imported
to Japan were written with it. In those days, India (天竺) [meant the promised
end of the world](https://japanese.stackexchange.com/a/73387/5010). Since the
8th century, 梵字 have been used in Japan as mysterious "symbols" that represent
Buddha, Gods and the "truth of the universe".

Today, only experts can read 梵字, but ordinary Japanese people do know they are
mysterious characters (or "symbols") related to Buddhism and ancient Asia.
Today, 梵字 are used mainly as mysterious design elements with an Asian and/or
religious flavor. A T-shirt is indeed one of the places where we see 梵字 often.
Asian wizards in fantasy works often use them when casting a spell. If I
understand correctly, it's similar to how Western people use [alchemical
symbols](https://en.wikipedia.org/wiki/Alchemical_symbol) and [runic
letters](https://en.wikipedia.org/wiki/Runic_magic) as mysterious design
elements.

