I recently purchased an 8 x 10 Tachihara and it came with a 10 x 12 back obviously made by Tachihara as the wood and hardware and finish match the 8 x 10 back. It uses a non standard (smaller size) of 10 x 12 film holder (the ground glass size is just under 10 x 12) and I am wondering if anyone has come across this 10 x 12 back before? I have done many google searches but can find no information about this back and information on related film holders. Thank you!