The center picture is of captured Chinese grenades. The complete photos from which the left and right cutouts are taken are:
Prisoner
Mountain Position
Communist forces in Korea used three basic types of hand grenades.
1. Offensive, or Concussion, grenades (upper right, 'potato masher'). Contain an explosive charge in conical body attached to a stick, designed for demolition effect and to stun the enemy in enclosed places, so the thrower can charge while the enemy is dazed.
In the bunker position shown, they would be useful in a quick counter attack on assaulting forces who became pinned down. During company-size assaults themselves, the Chinese armed entire platoons only with grenades, following them with other platoons armed with submachine guns, to take advantage of the stunned defenders. The grenade platoon members, when their grenades were expended, then armed themselves with weapons from either their fallen submachine gun platoon members, or from fallen defenders.
2. Fragmentation grenades (Stick-type in upper left, in hip pouchs and center; foreground. Pineapple-type serrated metal case in center picture, rear left, similar to our Mark II ). Contain an explosive charge in a metal body, attached to a stick, designed to break into fragments upon the charge exploding. Weighing about one pound, they have a killing radius of 5 to 10 yards, and fragments are dangerous up to 30 yards.
The stick-type grenade is armed by unscrewing and removing the wooden cap on top of the hollow handle. Inside the handle is a ring attached to a pull cord. A finger of the throwing hand is inserted in the ring, the handle grasped, and when the grenade is thrown the ring retains the cord, which ignites a friction primer which activates the delay element of a few seconds.
In offense, stray shrapnel makes fragmentation grenades something of a danger to attacking troops using them, but determined defenders are more able to recover and sustain their defense from the shock effect of the concussion grenades.
Chinese and North Korean stick-type fragmentation grenades were patterned after the Soviet RGD 33 hand grenades.
3. Chemical grenades (center, right) . Designed to produce a toxic or irritating effect, a casualty effect, a screening or signal smoke, an incendiary action, or some combination.
4. Bangalore Torpedo. This is just a 3 foot or so length of pipe, filled with flaked TNT or plastic like C-3, and capped at both ends. The fuze is screwed into one end of the pipe. It is primarily intended to blow paths through obstacles like barbed wire, and so is normally inserted under them, with the blast effect blowing the obstacle material up and to the sides.