Masudaya is a Japanese toy maker which became known as a leading builder of mechanical and battery operated toys in the post WWII era. Unlike most of their competitors, this company has managed to survive to this day, in part due to their involvement in the early days of the airsoft boom, during the early 1980s. The company was known for essentially creating the "skirmishable" airsoft gun. They were the first to design airsoft guns to be used for combat simulation. Before that, all airsoft guns were essentially for target shooting in your backyard.
Masudaya normally identifies their toys using the M-T, or Modern Toys logo. Most of the guns they produced, but especially the TradeMark series, are extremely rare. The Detachable series are the most common, followed by the Bolt series. The TradeMark guns are extremely rare. Many sources in the airsoft community in Hong Kong and Japan believe there are only a handful of each version of TradeMark guns left in existence. Also, some Masudaya guns can be seen packaged either as Masudaya or TradeMark. An example of this is the Thunderbolt, where some versions say "TradeMark" on the box and others just say Masudaya.
BS Buffalo and Detachable Series:
Masudaya also produced a small line of guns under their "TradeMark Air Guns" name. These guns included: