Masamune (Unequippable)

The unequippable version of the Masamune  is the key item obtained by the party of Chrono Trigger after they successfully reforge the Masamune in order to give it to Frog. Once this key item is given to Frog, he will permanently join the party, and it will be replaced in the player's inventory by the equippable (but non-upgraded) version.

Lucca helps in its reforging.