Originally Posted by
T-Mar
One piece of literature that I have for a pull-chain model (it looks like it might be the same model as the cut off image of your post) states that it came with a three speed freewheel.
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There's another Japanese company named Arai that manufactures motorcycle helmets.
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It's not surprising that there are multiple Arai companies, when you consider that it is a fairly common Japanese surname.
The derailleur you can see a bit of is a Shimano, a 333 if I remember correctly.
I know the Arai helmet company very well. My head is peanut-shaped so Japanese-market helmets don't fit me. I've been to their factory in Saitama, just north-west of Tokyo (and home of Toei cycles), a couple of times to have exports linings put into domestic helmets. As 'Chair' Arai are in Aichi (like Toyota and Suzuki), around 200 miles away in the West of Japan, I'd be very surprised if they were connected.
And as you rightly point out, Arai is a pretty common surname here. The present owner of Silk (ex-Katakura Silk) is called Arai, as is a guy in Tokyo who makes chainwheels to order.