Never seen one with that low a number, there are some model 50's but I don't know or any single digit Ideales. Nevertheless, it looks like what it is, an oldy but a good 'un, with some care and if the leather hasn't perished. From the black enamelled frame, small rivets and integrated saddle bag hanger loops, it looks like the equivalent to a Brooks B17 Standard, and like an early '40s model, probably low in the Ideale line. BUT, that doesn't mean you should neglect it, heck, it might even turn out to be the holy grail for some Japanese collector...so clean it carefully and apply some Proofide, nothing else.