[When Attacking] Your Leader gets +1 [Ki].
[Activate Battle] Place this card from a Battle Area into its owner's Drop: If you have a total of 4 or more [Ki], your "Son Goku" that's in a battle gains [Double Strike] for the battle. ([Double Strike]: This card inflicts 2 damage instead of 1 when attacking.)
[Ki]: An energy marker placed under a card.)