This was discovered in an attic clearance, it has an enscribed emblem in the stock which states: "Junior Sport Gun", under that it states the make or model as a "Blacky", followed by BS Gun, serial number K501, and made in Japan.

It appears to be very well constructed, with a solid hard wood stock, steel and alloy body & chamber/cocking lever, solid steel smoothbore barrel , which I would say is around 8mm in bore size?.

Its 32.5" in length.

It has a solid chromed steel trigger & well constructed trigger guard.
The rifle cocks and fires even after heaven knows how long in the attic. The condition as can be seen is reasonable, although the black enamel paint has suffered & it would benefit from some maintenance.

It is also missing a litttle swing out magazine, I am no machinist, but looking at it, it wouldnt take a genius to make a replacement.
I have never seen one like this, so the questions are has anyone else? how old is it?, are they collectable? and does it have any value?.
It will be up for sale, but I have no idea on its origin or collectable value.

Thanks for any input, I am sure someone will recognise it!