Gradual Discharge Matchlock (緩発式火縄銃)

Gradual discharge matchlock is a gun with a type of matchlock explosion mechanism, 'gradual discharge.'

There are two types of explosion mechanism: 'instantaneous discharge' and 'gradual discharge' with matchlocks, and Japanese matchlocks are classified as instantaneous. By contrast, the gradual ones are prevalent in Europe, China and other areas.

Matchlock is fired when a match-mounted arm called 'serpentine' is set in motion by pulling the trigger to ignite the priming powder in the flashpan.
The mechanism which makes the arm move slowly at the rate of pulling the trigger to ignite the priming in the flashpan is called 'gradual discharge.'
The system in which the arm instantly strikes the flash pan driven by the lock mechanism is called 'instantaneous discharge.'

The gradual discharge is said to have small risk of accidental discharge by touching the trigger alone but have lower accuracy. The arm which remains to be lifted by spring action is gradually pressed down by pulling the trigger, therefore if the trigger is released, the arm returns to the lifted position. See instantaneous discharge matchlock for comparison between the two systems.