Lock

"Lock" ( Rokku) is a keyword, which refers to the action to change the state of a rear-guard to be a locked card, and introduced in Trial Deck 11: Star-vader Invasion.

In the anime, Lock is visually shown as two black rings collapsing onto the unit reverting it into card form and on the table, the face down card is shown to emit sparks when the player attempts to touch it, and at the end of the turn, all cards that were affected return to be face up automatically without making a turn. '''[This page is fan made, and all the details here is copied from original if any one want to added their link joker card, feel free to add] '''

How it Works
When a rear-guard is locked, it turns face down and remains face down on the circle it was locked on until the end of its owner's turn. A locked card loses all characteristics present on its face-up side, as well as other characteristics that it received before being locked. A locked card is not a rear-guard (and hence it is not a unit either, although it is still regarded as a card, specifically a "locked card"), and while it is locked, the circle where it is on is not regarded as a rear-guard circle, but as a "locked circle". A locked card has no standing or resting state by game mechanic, but physically, the player is free to choose the orientation to place their locked cards (being vertically the most common).

Since a locked card is not a unit, it cannot be used to perform any action; it cannot attack, boost, intercept, use abilities, be used to pay costs, be moved to another circle or zone, or be retired by calling another unit over it. A locked can only be used by effects that explicitly affect a locked card or any cards in general. Including the locked circle, it can only used by effects that explicitly say "locked circle" or any "circle" in general.

Unlock
When a locked card will be turned face up, the action is known as "unlock" ( Anrokku). It means "turn the locked card face up in [Stand] state", which normally occurs at the beginning of the owner's end phase after it was locked. A locked card that is unlocked returns to being a rear-guard in the circle where it is located. However, the unlocked card is considered to be a different card than the original, and therefore, all effects that received card before it was locked disappear (For example, if the unit had to leave the field at the end of turn, this does not happen since it was locked). Also, the unlocked card is not considered as being placed on the circle, and so "placed on" effects are not activated.

Omega Lock
"Omega Lock" ( Omega Rokku) is a special variation of lock.

When a locked card is affected by Omega Lock, during the owner's next turn, on his/her end phase, they cannot unlock that card. Said locked card will only be unlocked during the owner's next end phase after it is affected. However, locked cards affected by Omega Lock still can be unlocked normally or with effects during any phase in any turn, excluding the "next end phase" where they cannot be unlocked by anything. If a locked card is affected by Omega Lock multiple times in the same turn, it will not prolong the Omega Lock's duration of two turns. In the card text, Omega Lock is referred as "cannot be unlocked during the next end phase".