- "I can see a future where you understand your weakness and ally with me. Now, my treasured mallet! Impart the power of dreams to all the speechless tools!"— Shinmyoumaru Sukuna (Double Dealing Character Stage 6.)
The Miracle Mallet (打ち出の小槌 uchide no kozuchi) is a legendary artefact from the tale of Issun-bōshi, a small hammer with the power to change an object's size. The diminutive protagonist steals the mallet from an oni, using its power to grow to the size of a normal human.
In the Touhou Project, the mallet's powers function only for members of Issun-bōshi's race, the inchlings, with its primary wielder being Shinmyoumaru Sukuna. In addition to size-changing, it can grant the wishes of the wielder, but at a cost proportional to the scale of the wish.
The energy emitted by the Miracle Mallet has the power to create tsukumogami, though this effect seems to be only partially under the user's control. Some time prior to the events of Hopeless Masquerade, this power began "corrupting" Reimu Hakurei's purification rod and Marisa Kirisame's Mini-Hakkero, increasing their power but making them harder to control. By the time of Double Dealing Character, these weapons, along with some of Sakuya Izayoi's knives, were capable of moving around on their own. After the resolution of the incident Shinmyoumaru began withdrawing these energies back into the Mallet, and by the time of Forbidden Scrollery chapter 12, the weapons have completely returned to normal. Some newborn tsukumogami however, including Benben, Yatsuhashi and Raiko, found alternate sources of power that allowed them to remain in existence.
The Mallet's energies also have mind-influencing effects, with a number of normally peaceful youkai going berserk during its appearance. After the events of Double Dealing Character, it was realised that tsukumogami created by the Mallet were unusually passive towards their human owners. Likewise, their owners became more youkai-like in behaviour, and oddly unconcerned with their tools' strange new properties.
In the game Impossible Spell Card, the amanojaku Seija Kijin manages to obtain a replica of the magic mallet, however it was very different from the original. In fact, the replica does not have the power to grant wishes or change the size of objects, but allows Seija to deal blows to her opponents in the but to get rid of them more quickly. However, in the Gold Rush mini-game, this time Seija steals the real magic mallet belonging to Shinmyoumaru, thus described as "the ultimate object for breaking all the rules". Seija uses it to loot the Hakurei Temple, and more specifically to transform Reimu Hakurei's danmaku into gold coins, called koban.