Sea GateHow it works & interactions with other cards

What it Does

Sea Gate provides a constant source of Blue mana, but its true power lies in its flexibility. Upon entering the battlefield, you select a color that is not blue (White, Black, Red, or Green). From that point forward, the land can be tapped to produce either Blue mana or one mana of the color you specifically chose for that instance of the land.

How it Resolves Step by Step

When you play Sea Gate, it enters the battlefield tapped. This is a replacement effect, not a triggered ability, so it does not use the stack. At the exact moment it enters, you choose a color other than blue. This choice is also a replacement effect and cannot be responded to by opponents. Once the land is on the battlefield, it has an activated mana ability that allows you to tap it for Blue or the chosen color whenever you have priority or are prompted to pay a mana cost.

When to Play it

Since Sea Gate enters the battlefield tapped, it is best played during turns where you do not need to use all your available mana immediately. It is ideal for decks that require heavy Blue mana but may have difficulty hitting their secondary color requirements early in the game. Because it has the Gate subtype, it is also a perfect addition to decks that include cards with 'Gate' synergy.

Common Mistakes

A common point of confusion is thinking you can change the chosen color later; once the choice is made as it enters the battlefield, that choice is locked in as long as that specific permanent remains on the battlefield. Additionally, note that you cannot choose Blue as your secondary color, even if your deck is mono-blue. Finally, if the land is put onto the battlefield without being 'played' (via a spell or ability), you still make the color choice as it enters.

Interaction examples

Comparing Universal Fixing

Command Tower

In a Commander game, if you have both cards, Command Tower provides immediate mana of any color in your identity without entering tapped. However, Sea Gate serves as a redundant fixer. If your commander is Blue and Green, you can play Sea Gate choosing Green. While Command Tower is faster, Sea Gate ensures you have your secondary color fixed for the rest of the game once it untaps.

Opponent Interaction

Exotic Orchard

If your opponent controls an Exotic Orchard and you control a Sea Gate for which you chose Red, your opponent's Exotic Orchard can now produce Red mana. This is because Sea Gate 'could produce' Red mana based on the choice you made as it entered, expanding the utility of their land based on your strategic choice.