The strategy site introduces the mechanic formally to the TCG.
Below are some of the key takeaways of the article. We suggest you check out the full version here for more information. We’ve also updated our previous Link Summon Rules article with TCG terminology for those that want additional help with getting accustomed to Link Summoning.
Extra Link as defined by the Official TCG Strategy Site occurs…
“…when a series of co-linked Link Monsters is built that connects a Link Monster in an Extra Monster Zone to a Link Monster in the other Extra Monster Zone.”
The only exception to the rule that states “you can only control 1 of the 2 Extra Monster Zones” is…
“…If Link Summoning to the second Extra Monster Zone would create a complete series of Extra Linked Link Monsters, you may Link Summon a monster to that Extra Monster Zone to complete that series.”
Notably, the strategy site goes out of its way to mention that…
“Link Monsters can be co-linked on diagonals, though at the time of this writing there are no Link Monsters whose Link Arrows point diagonally upwards. If at some point such Link Monsters were to exist, they could also be used this way.”
While currently the only depictions of an Extra Link are in a U-shape, the article notes that there are no Link Arrows that point diagonally upwards yet, suggesting that other formations could be possible in the future.
Additional bits of information of interest include:
“Any Link Monster that is co-linked to one of the monsters in this series is also Extra Linked, even if it’s not contributing towards making the monsters Extra Linked.”
This means that you can have monsters like Honeybot, or soon, Proxy Dragon, in the farthest left or right monster zones and still be part of the Extra Link. In addition…
“You don’t have to control all of the Link Monsters in the chain in order [to form an Extra Link]”
So in those rare cases where the opponent has Link Monsters in their main monster zone, but controls none of the Extra Monster Zones, you could possibly use their monsters to take control of both Extra Monster Zones for yourself.