Unspeakable Formation

is the Noble Phantasm of Sima Yi. Properly called .
The essence of the human known as Sima Yi is not that of a strategist that pulls clever schemes and is a rare genius. Naturally arranging whether it’s warfare or authority conflicts, naturally waiting for time, naturally winning, she mutters a song that isn’t unpleasant but can’t be liked.
Simply put, it is a Noble Phantasm that “crushes an enemy’s strengths and exposes their weaknesses”.
When the illusory sun and full moon appear over the horizon, the world transforms and all kinds of mystics lose their meaning. In this case, this Noble Phantasm does not erase or nullify them. For example, it instead changes the battlefield into a sea against a Mystic Sword that can cleave land, or reduce the mana in the surroundings against a Servant skilled in magecraft.
At the time the phantom sun and moon appear from the horizon, the forte of the enemy is crushed, and the hidden weak points are exposed. If enough conditions like "being a once defeated enemy" or "having already gathered all the enemy’s data" are met, it becomes a joker killer that can even "create a weak point".
Because this formation has no form, even those casted on have no means or words to describe it. Therefore, it is called the Unspeakable Formation.
==References==
Category:Noble Phantasms
Category:B rank Noble Phantasms
Category:Anti-Formation Noble Phantasms
Category:Noble Phantasms introduced in Fate/Grand Order