When researching Japanese sirens, these 3 recordings always seem to come up (especially the first two). I guess these are Japan's equivalent to the famous HOR Siro Drone recording that is always used in movies. All 3 are different types of Japanese sirens I would assume, though the 2nd also sounds exactly like some types of Russian siren. https://www.youtube.com/watch?v=e8FO9vJqMzQ
Russian siren that sounds like 2nd siren in videohttps://www.youtube.com/watch?v=LujeVypleP0
Japan has 6, 8, 9, and 12 port sirens along with a few 6/12 port dual tone units. Videos of the 8 port ones online are mostly in areas with 60 Hz AC, so they sound just like American sirens. The others are found on both 50 and 60 Hz in random videos online, with the 12 port ones being found mostly on 50. Their 9 port sirens will sound like either a Hormann E57 or ACA Screamer S-2/5/7.5, and the 12 port ones will sound like a Sentry 14V/40V1T or an STH-10. I think the 6 and 9 port ones are used as fire and CD sirens, while the 12 port ones are mostly used as either dam or flood sirens. It varies from area to area, but that's the general trend I've seen.