Tessaiga, Fang Reforged

At the beginning of combat on your turn, put
a charge counter on Tessaiga, Fang Reforged.

Equipped creature gets +1/+1 for each counter
on Tessaiga, Fang Reforged.

As long as Tessaiga, Fang Reforged has for or more counters on it, equipped creature has double strike.
Equip—Pay{3} or remove a counter for Tessaiga, Fang Reforged.