Underground Sea
90% of drawn Underground Seas are played before the game ends, and decks that resolved it won 32% of the time compared to 24% when it stayed buried, an early signal of a +7.8 percentage-point lift.
Underground Sea sits in 13% of tracked Commander decks on Playgroup Live, with 540 of 4312 distinct decks bringing it to a live game. When it reaches a player's hand, 90% of those copies get played before the game ends, one of the highest draw-to-play rates of any land in the dataset.
The win-rate signal is worth noting, though both sample sizes matter. Participations where Underground Sea resolved show a 32% win rate (n=353), against 24% for games where it never left the library (n=595). That's a +7.8 percentage-point gap. With sample sizes in this range the effect is directional rather than conclusive, but it points consistently in one direction across what we've tracked so far.
The card's reputation precedes the data. Underground Sea is a Reserved List dual land, fetchable, and produces both blue and black with no drawback. It sees play across 5-color piles and dedicated Dimir or Grixis shells alike. The spread of commanders in the top-10 list reflects that breadth: five-color commanders dominate simply because they have the most decks in the pool.
- 13% of tracked Commander decks include Underground Sea
- 90% of drawn copies are played before the game ends
- T3.0 median turn Underground Sea first enters play
- 88% battlefield stickiness once it resolves
- +7.8pp win-rate lift observed when Underground Sea resolves vs. stays in library
- 387 distinct players have brought Underground Sea to a tracked game
First-cast turn
n=392The "good card" funnel
1180 brought · 387 playersOf 1180 Underground Seas brought to games, 435 were drawn, 392 reached the battlefield, and the large majority stayed there through the end of the game.
Players who cast this card win 32% of the time (n=353) , vs 24% when it never left the library (n=595).
When players drew this card but left it in hand, they won 23% (n=37) — about the same as leaving it in the library. Those players survived long enough to draw it, so the gap above is about the card resolving, not just about surviving.
Observed gap +7.8pp; 95% confidence interval +2.4pp to +13.2pp. Correlational, not causal: powerful payoffs also get cast more often in games you are already winning.
Final zone distribution
481 instancesMost Underground Seas that enter a game finish on the battlefield rather than in the library, reflecting how reliably players draw and deploy this dual land before games conclude.
Commanders that played this card
in tracked games-
1
The Ur-Dragon
32 decks
-
2
Y'shtola, Night's Blessed
21 decks
-
3
Esika, God of the Tree // The Prismatic Bridge
17 decks
-
4
Captain N'ghathrod
13 decks
-
5
Marneus Calgar
12 decks
-
6
Teval, the Balanced Scale
12 decks
-
7
Jin Sakai, Ghost of Tsushima
11 decks
-
8
Kenrith, the Returned King
11 decks
-
9
Oloro, Ageless Ascetic
11 decks
-
10
Tymna the Weaver
11 decks
Five-color commanders dominate the top spots by raw deck count, but that reflects population size more than any special affinity for Underground Sea specifically.