It looks externally similar to the Walther TPH, except it is blockier, like the Makarov PM or Browning "Baby". It is chambered for the rimless 7.65x17mm Type 64 round used in the Type 64 silenced pistol.
Internally, it is a single-action striker-fired blowback-operated pistol with a one-piece wraparound polymer grip and a single-stack 7-round magazine. The simple iron sights are notch and post. It has a fluted chamber to aid in ejection of spent cases or extracting misfired rounds. The magazine release is located on the left side below the trigger guard and the manual safety catch is located on the left-hand side of the frame above the grip. There is a small lanyard ring on the bottom of the grip frame.
The weapon uses the unique Einhandpistole (German > "one-handed pistol") cocking system, requiring the use of only one hand to cock the weapon and use the magazine release and safety catch. This was developed in the early 20th-century by Witold Chylewski of Bergmann Waffenfabrik and used on the Lignose Model 2A and Model 3A pistols (variants of the conventional Bergmann Model 2 and Model 3). In this system, the slide is linked to the upper part of the trigger guard. It is cocked by extending the trigger finger and pulling the trigger guard (and thus the slide) back along a groove in the lower trigger guard until it hits the return spring. When the trigger guard is released, the slide moves forward, chambers a round and cocks the weapon. Until the trigger is pulled, the trigger guard remains locked forward to prevent it pinching the operator's trigger finger.
The Type 77 is the starting sidearm of your character. It should be exchanged as soon as you obtain another pistol due to very low damage and a small clip (the smallest of all 3 pistols). It is used during your escape from the mall prison. If you are playing as Rios, you will manually kill a guard and take his pistol. If playing as Salem, Breznev will kill the guards outside your cell and open your door, at which you need to take a pistol.