Citadel Gate

Half of this land's fixing is settled before the game starts. White is always available; the second color locks in the instant the land arrives and never shifts again. That one-time declaration is the whole quirk of the design: a manabase leaning on these wants you to know your splash before you shuffle up, not to keep options open tap by tap. The permanent white side makes it a clean way to bolt a white splash onto a deck without contorting your other lands around it. Then there is the Gate typing, which explains why it wears this exact shape rather than existing as a nameless enters-tapped dual. Left alone it produces two colors at a taxed, always-tapped rate and does nothing else. But a handful of cards care about counting or controlling Gates, and this land pads that total as much as it smooths colors. That double purpose is the fair way to read it: as a plain dual it is slow and forgettable, deliberately so, while as a member of a subtype that turns lands into a countable resource, it is a cheap unit that also happens to make mana. Most players will only ever register the tapland. The Gate line is the reason it looks the way it does.