Deckbuilding basics

Before a game, each player builds a deck. A deck is four things: a Legend, a Main Deck, a Rune Deck and three Battlefields.

• Legend: one card. It sets your two Domains.
• Main Deck: at least 40 cards, your Chosen Champion counted in the 40. Only units, gear and spells go in it.
• Rune Deck: exactly 12 runes, each one of your Legend's two Domains. Any split works: 6 and 6, or 5 and 7.
• Battlefields: 3, all different. You use one in a game.

• 
  Wuju Bladesman: Calm and Body. Every card in this deck must be Calm, Body or both.
• 
  Master Yi, Meditative: the Chosen Champion — a champion unit with the same champion tag (Master Yi) as the Legend.

Two more limits. You can have at most 3 copies of any card name. And a Signature card only goes in a deck with its own champion's Legend, so Ahri's Fox-Fire can't go in a Master Yi deck. A deck may hold at most 3 Signature cards.

Riot also keeps a ban list: a few cards you can't use in organized play. Check it before you copy a deck from somewhere.

Below is the Master Yi starter deck you'll play with in this chapter. For each change, guess whether the deck is still legal, then see why.

Try it

Is this deck legal?

×6

×6

Battlefields

Main Deck · 40 cards

×2

×2

×3

×3

×2

×3

×3

×2

×3

×2

×3

×2

×2

×3

×2

×2

‹

1 of 9

›

Add a 4th Stalwart Poro

• Stalwart Poro: 3 → 4

Still legalNot legal

0 of 9 changes tried.

From the Core Rules (2026-10-09): 103 — Deck Construction · 103.1 — the Legend and Domain identity · 103.2 — the Main Deck: 40 cards, 3 copies · 103.2.d — Signature cards · 103.3 — the Rune Deck · 103.4 — no two Battlefields of the same name · 487.4 — a Duel's 3 Battlefields