During the Chinese civil war in the 1920s and 30s, international arms embargoes made rifles difficult to acquire – which led to a lot of popularity for pistols with shoulder stocks. The C96 “broomhandle” Mauser in particular was popular, and it was copied by a number of Spanish firms for sale in China as well (in fact, the fully automatic Schnellfeuer version was initially made by Mauser specifically for Chinese sale). The .45 ACP cartridge also became popular with Thompson submachine guns in some areas, and the natural result was a Chinese arsenal designing and producing a C96 Mauser pistol scaled up to use .45 ACP. A few thousand of these were originally made in Shansei from 1928-1931, and then another batch was made for export in the 1980s. They are actually the same basic size as the C96 (and retain the 10-round capacity), but are much wider and heavier.
This Shansei Broomhandle is one from the relatively recent commercial batch, which should make it more affordable and less worrisome to shoot than the nearly 100-year-old originals.