Welcome. Neat looking machine. What's behind the bulge in the nose?
Sanshin would be the manufacturer. Japanese companies would put any brand the buyer wanted on their machines as long as they bought enough of them. That or leave the brand off and the buyer would put their own brand on. It could go either way. It's common to find several different brands on what is basically the same machine. The belt might be a replacement. I want to say Alphasew is still around. It's also possible the belt is original. Either way I wouldn't go by what it says for machine ID purposes. I think I read that there used to be a high tax on importing motors here, also not every country uses 120VAC as the standard voltage. Sewing machine companies would ship the machines without motors and install them where the machine was to be sold.
Japanese companies made a lot of Singer 15 clones. A lot of Japanese machines are descended from those Singer 15 copies. Your machine uses basically the same bobbin/hook assembly as a Singer 15 but the rest has been changed.
Rodney