Harmonized Kodachi

Once per Turn Action -

: Attack

If you have a card in your pitch zone with cost 0, this card's attacks get go again.

Rulings

From the Crucible of War release notes

It is possible for Harmonized Kodachi to gain go again after the attack has been declared if a card with cost 0 enters the pitch zone before the chain link resolves.
You can only pitch when there is a cost to pay.
Harmonized Kodachi is looking for cards in your pitch zone with a defined value (cost 0). A card with no resource cost, such as Heart of Fyendal or Cracked Bauble, do not have this defined value, and are ignored by Harmonized Kodachi’s effect.
You may start the game with up to two Harmonized Kodachi in play as they are 1H.

From the Welcome to Rathe release notes

You may start the game with zero, one or two Harmonized Kodachis as it is a 1-handed weapon. (We highly recommend choosing 2.)

Keyword notes

Go again - Go again allows multiple actions to be played in a turn when usually playing an action with use up your action point, and therefore end your turn. A card with go again gives the controller of that card or activated ability 1 action point when it resolves.

When an action with go again resolves, its controller gains 1 action point.
Multiple instances of go again on the same card or activated ability do not stack. If a card or activated ability has multiple instances of go again when it resolves its controller gains 1 action point only.
If an action with go again does not resolve, its controller does not gain 1 action point.
You cannot reveal a card with no to Belittle. The card must have a value to its power that is 3 or less. (0 is a value)