The Type 64 was the first in a series of suppressed Chinese submachineguns. Introduced in 1964 (as you might have guessed), it used a simple blowback action chambered for 7.62x25mm cartridges. It was designed to use a heavy, subsonic variety of the round, but could fire standard ammunition if necessary.
Many parts of the Type 64 bear a strong resemblance to Chinese AK parts, including the magazine catch, stock, pistol grip, and safety lever.
One interesting aspect to the Type 64 is its reportedly very high cyclic rate or around 1200 rpm. This is due to a combination of an unlocked blowback action, relatively energetic cartridge, and added backpressure from the suppressor.