Anybody here likes bats?
The use of (existing) animals in sword koshirae or armors can have different meanings. Either it can be a reference to the owners life (place of birth, nickname, story, local lore etc) but also Shinto and Buddhist references are often made.
Specifically about the bat: Koumori (??? ) koshirae can also have multiple meanings but all can be traced back to Chinese culture.
In contrary to Western lore and culture where the bat is a dark creature of the night ("I'm the goddamn Batman" :-) ), the bat has a completely different meaning in the Asian culture.
In Asian cultures, the bat symbolizes fortune or good luck. The reason for that is quite simple since ?? (the symbol for bat in Chinese) is pronounced like 'Fu' which sounds similar to 'luck'.
A second main reason is a story about the rat (Chinese astrology). According to legend, the rat who lives a 100 years will transform into a bat so it also symbolizes a long life and wisdom.
The story of ascension is quite common in Asian culture and there are many legends about transcending due to persistence and hard work.
Since these stories are very much part of the Asian culture, could that be a reason for the modern performance driven society? (not trying to get racial here).
Another beautiful story is the one of the legendary koi. The koi was so persistent that he never gave up trying to jump up against a waterfall. After many failures he finally succeeded and was awarded immortality as a dragon by the gods. But that's gonna be another story we'll save for next time ;)