Barian Untopia X SPELL Field (This card is always treated as a "Barian's" card.) "Number" monsters you control with a number between "101" and "107" in their name, as well as "CXyz" monsters and "Number C" monsters you control, cannot be destroyed by your opponent's card effects, and your opponent cannot target them with card effects
The best answer for this card is itself, which can lead to many matches becoming a Bowmasters-off
For example, removing a Blightsteel Colossus with it is usually a good trade, but I wouldnt target something like an Arcane Signet
That way, you always know todays price, not last months
This means in general, basic land is only good for keeping parity with your opponents in the early stages
You know how to set up a game, what to do on your turn, and how to attack