Sanity Grinding — ruling 1

Chroma abilities check only mana costs, which are found in a card’s upper right corner. They don’t count mana symbols that appear in a card’s text box.

Sanity Grinding — ruling 2

Chroma abilities count hybrid mana symbols of the appropriate color. For example, a card with mana cost {3}{U/R}{U/R} has two red mana symbols in its mana cost.

Sanity Grinding — ruling 3

If there are fewer than ten cards in your library, reveal them all. For each blue mana symbol in those cards’ mana costs, the targeted opponent puts the top card of their library into their graveyard. Then you reorder your entire library as you choose.

Sanity Grinding : règles, fonctionnement et interactions (MTG)

Sanity Grinding is one of those cards players keep asking about. Here is, in plain words, what its official text says, the rulings published by Wizards of the Coast, and the combos players actually run.

Official card text

Chroma — Reveal the top ten cards of your library. For each blue mana symbol in the mana costs of the revealed cards, target opponent mills a card. Then put the cards you revealed this way on the bottom of your library in any order.

Complete guide

Sanity Grinding is a powerful mill spell that harnesses the Chroma mechanic to turn your library's blue mana symbols into a weapon. By revealing the top ten cards of your deck, you can force an opponent to lose a massive chunk of their library in one go. It is a cornerstone for mono-blue strategies that want to win through exhaustion rather than damage.

Harnessing Chroma

When you cast Sanity Grinding, you reveal the top ten cards of your library to check their Chroma value. Specifically, you are looking for every blue mana symbol printed in the upper-right corner of those cards. Hybrid symbols like {U/R} count as a blue symbol for this check. Symbols in the text box, however, do not count toward the total.

Resolution Steps

First, you target an opponent as you cast the spell. Upon resolution, you reveal the top ten cards of your library (or your entire library if it contains fewer than ten). Count the total number of blue mana symbols among the revealed cards. The targeted opponent mills that many cards from the top of their library. Finally, you take the revealed cards and place them on the bottom of your library in any order you choose.

Common Mistakes

Players often forget that Chroma only counts symbols in the mana cost. If you reveal a card with a blue activated ability but a colorless mana cost, it contributes zero to the mill count. Additionally, because the cards go to the bottom of your library rather than the graveyard, you cannot easily recur them or use them to fuel 'delve' mechanics immediately after the spell resolves.

When to Play It

Sanity Grinding is most effective in decks with a high density of blue mana symbols, such as those featuring 'heavy' blue costs like {U}{U} or {U}{U}{U}. It is best played after you have used scrying or library manipulation to ensure the top ten cards of your deck are packed with blue symbols, maximizing the impact of the mill.

Interaction examples

The Chroma Count

Fabricate

You cast Sanity Grinding targeting your opponent. Among the ten cards you reveal is Fabricate. Because Fabricate has a mana cost of {2}{U}, it contributes exactly one blue mana symbol to the total count. If the other nine cards were lands, your opponent would mill only one card.

Refilling the Library

Windfall

If you have used Windfall to discard several cards and draw into Sanity Grinding, you might be low on cards. If you cast Sanity Grinding with only five cards left in your library, you reveal all five. You count the blue symbols among those five, the opponent mills that many cards, and then you put those five cards back on the bottom of your library in any order, effectively reordering your remaining deck.

Guide written with AI from the official text and rulings. Official English text prevails.

How it works : Sanity Grinding

Original English text — Wizards of the Coast / Scryfall

#1August 1, 2008· Wizards of the Coast
Chroma abilities check only mana costs, which are found in a card’s upper right corner. They don’t count mana symbols that appear in a card’s text box.
No other card is named in this ruling.
#2August 1, 2008· Wizards of the Coast
Chroma abilities count hybrid mana symbols of the appropriate color. For example, a card with mana cost has two red mana symbols in its mana cost.
No other card is named in this ruling.
#3August 1, 2008· Wizards of the Coast
If there are fewer than ten cards in your library, reveal them all. For each blue mana symbol in those cards’ mana costs, the targeted opponent puts the top card of their library into their graveyard. Then you reorder your entire library as you choose.
No other card is named in this ruling.