: Add one mana of any color.City of Brass gives a multicolor mana base immediate access to any color from one untapped land. It is useful when your deck’s early spells span several colors or when leaving one land available needs to represent different possible answers.
Its cost is expressed through a triggered ability: whenever City becomes tapped, it deals one damage to you. That includes being tapped by another effect, not just activating its mana ability. Mana Confluence fills a similar fixing role but uses a life payment as an activation cost, so the two lands are not mechanically identical.
Reflecting Pool works well beside City because it can produce any color City could produce without inheriting the damage trigger. In a deck that needs dependable access to many colors, this pairing can make later land drops more flexible while reducing how often you must tap City itself. Arcane Signet can support the same goal by adding another source that covers your commander’s colors.
City remains a nonbasic land with no basic land types, so fetch lands such as Polluted Delta cannot search for it. It also provides only one mana at a time, making it a fixing piece rather than a ramp engine. Repeated damage adds up when you use it throughout a long game or untap it multiple times. Include it where avoiding a missed color is worth that cost, and support it with enough lower-cost mana sources to keep the life pressure manageable.
