Tsukuyomi (月読 Tsukuyomi) is a Caster Magic which was invented as an antithesis to Amaterasu.
In stark contrast to Amaterasu, Tsukuyomi consists of naught but a single formula. Said formula can only be cast through the performance of five mudra in the correct order. However, it should be noted that it's entirely possible to cast imperfect variants of the formula by performing the five mudra in any of the wrong orders. Thus, Tsukuyomi consists of 1 perfect formula and 119 imperfect formulas.
Also, Tsukuyomi's formulas do not explode like Amaterasu's formulas. Instead, Tsukuyomi's formulas implode upon their contents in order to either pulverize their contents or squeeze their contents to the point where the contents will be unable to move from their location.
Lastly, instead of counting up like Amaterasu's formulas, Tsukuyomi's formulas count down. Thus, Tsukuyomi Formula 1 is the perfect formula while Tsukuyomi Formula 2 - 120 are the imperfect formulas.