Extra Link

An Extra Link (Japanese: エクストラリンク, Ekusutora Rinku) is a series of co-linked Link Monsters that connects one Extra Monster Zone to the other. The monsters that make up the Extra Link are considered to be Extra Linked; additionally, any monster co-linked to an Extra Linked monster is also Extra Linked. An Extra Link is formed regardless of which player controls the monsters, including the monsters in the Extra Monster Zones.

It is possible to create an Extra Link using fewer than five monsters by co-linking them diagonally, although there are currently no Link Monsters with the Link Arrows to accomplish this feat.

Using an Extra Link to control both Extra Monster Zones
If Link Summoning a Link Monster in an Extra Monster Zone would create an Extra Link, the player can do so even if they already control a monster in the other Extra Monster Zone; this is the only way for a player to control monsters in both Extra Monster Zones simultaneously.