The other really easy way to meet Japanese girls is through Language Exchanges.
These are one-on-one meets where you practice speaking Japanese with a native while they practice speaking English/French/German/Italian/Korean/etc with you.
Not surprisingly, many Japanese girls/guys who are interested in practicing a foreign language are also quite interested and open to dating a guy/girl from that country.
Many times it’s a lot more like a coffee date than a language exchange.
Japanese are especially uncomfortable with really assertive styles of communication and easily feel bullied, so will often seem to be saying “yes” even when they mean no.