The Type 98 mortar was designed in the late 1930s to support assault on fortifications; however, it would see the majority of its use as a fixed weapon emplaced in gun pits for close-in defense.

According to Japanese sources its destructive firepower was roughly equivalent to a 203mm heavy conventional artillery piece.

The 300 kg (660 lb), 1.5 m (4 ft 11 in), 330 mm (13 in) shells fit around and on top of the tube, instead of being dropped inside, making this a spigot mortar.

[3] To absorb the massive recoil caused by firing their projectiles, the mortar tubes were almost always placed up against a mound of dirt.

[7] Due to the relative difficulty[4] involved in moving such a massive weapon system, their locations usually remained fixed during battles.