The Masamune

The trigger event doesn't have to specifically refer to "creatures." In these cases, the trigger event may also refer to something being "put into a graveyard from the battlefield." For example, if the equipped creature or an emblem you own has an ability that triggers "whenever an artifact is put into a graveyard from the battlefield," that ability would trigger twice if an artifact creature died.

If you somehow control two of The Masamune and they're equipped to creatures you control, a creature dying causes abilities of emblems you own to trigger three times, not four. (If they're equipped to the same creature, the abilities of the equipped creature will also trigger three times.)

The granted ability's effect doesn't copy the triggered ability; it just causes the ability to trigger twice. Any choices made as you put the ability onto the stack, such as modes and targets, are made separately for each instance of the ability. Any choices made on resolution, such as whether to pay a cost for that triggered ability, are also made separately.