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See also: Thaumaturge, Thaumaturgical weapons

Thaumaturgy is the general name for the science of magic in Bas-Lag. The term encompasses a wide variety of sub-practices, all of which generally involve the channeling of energies and the use of fetishes or technological aids, such as chymical vials and clockwork devices.

In New Crobuzon, practitioners of thaumaturgy are called thaumaturges. Other cultures, such as the Grindylow and the Vodyanoi, combine thaumaturgy with religious elements of shamanism. The spells and techniques of thaumaturgy are typically referred to as "hexes" or "charms".

Fundamentals of thaumaturgy[]

At its most basic, thaumaturgy involves channeling energies through the user's body, which can result in physiological effects on the user over time. As part of channeling the energies of the hidden science, thaumaturgies use finger signs and vocal components. This process can also result in sparks generating from the user's fingers, as well as spilled blood boiling off as the thaumaturgical energies dissipate.

While all thaumaturges can use thaumaturgy without any aids once trained in the art, the use of thaumaturgy is enhanced by fetishes and chymicals which allow the user to increase the power of their act.


New Crobuzon thaumaturgy[]

Most New Crobuzon thaumaturges are trained at the city's premier university, New Crobuzon University. Thaumaturges here learn a variety of hexes, few of which are explained in detail. A very few of the known hexes include:

  • Clayflesh Hex - Used by bio-thaumaturges to Remake individuals. A Clayflesh Hex is normally akin to a surgical procedure, requiring the assistance of dedicated tools and fetishes to use effectively. However, some skilled users like Montague Vermishank are able to use the hex on demand, with only a few moments of preparation.
  • Veil-hex - A concealing hex that "makes shadows sticky" to the user. It requires stepping into the deepest shadow that the user wants to cover them, and channeling energy to make the shadow cover the user even after they step into a lit area. The shadows extend about an inch off of the skin of the user, making it difficult to watch them.
  • Unnamed hexes
    • A hex to put dogs to sleep
    • War hexes that cause spikes of energy to erupt from the ground and pierce their targets, setting them on fire with a black flame. There are multiple hexes with this effect, although their colors and scales differ. Some can be executed by a single thaumaturge, with considerable effort, while others require multiple thaumaturges to link hands.
    • Unnamed ranged hex that manifests as a disturbance in the air, shooting from the caster at a target.

Defensive thaumaturgy is used to protect important places, such as the mayor's residence. This thaumaturgy includes charms that protect against explosions, bullets, and other shrapnel, although it is not enough by itself to repel intruders.

Teshi thaumaturgy[]

Teshi thaumaturgy is alien compared to that practiced by New Crobuzon. Although details are vague, Teshi thaumaturges are able to cast a variety of strange hexes. Known examples include:

  • A hex used on the battlefield that causes the victim to grow extra limbs.
  • A hex used on the battlefield that turns the victim's eyes into hemorrhaging blood-sacks and cause them to "see the death in everything".
  • Flesh-melting hexes that can be used as a form of suicide bombing in battle.


Teshi ambassadors are potent thaumaturges trained in a variety of hexes, referred to as "ambassadormagick". It is not clear whether all of a Teshi ambassador's skills are a function of the hecatomb ritual, or whether they can be used independently without beginning the ritual.

  • The Hecatomb ritual, which includes the ability to use acausal manifestations, "haints", to attack enemies in close range.
  • A passive hex that causes all physical attacks to miss.
  • A hex that allows the user to bend space around them and instantly move an arbitrary distance when they break line of sight with anyone watching them.
  • A hex that embeds an enemy in an inanimate object, such as a wall, making a pushing motion and causing the object's matter to reach out and yank the target into itself.

Vodyanoi thaumaturgy[]

Vodyanoi use a specific type of thaumaturgy, referred to as Watercraeft, which involves the manipulation and sculpting of water. In comparison to the thaumaturgy used by most of New Crobuzon, its principles are poorly understood.

Grindylow thaumaturgy[]

Grindylow thaumaturgy seems to primarily deal with the manipulation of space, allowing the user to move in impossible ways to evade detection among other abilities. Utilizing the thaumaturgy involves communing with grindylow ancestor-spirits, and thus the most powerful grindylow thaumaturges are shamans and assassin-priests. In one particular case, the thaumaturgy required becoming the symbolic lover of a grindylow relic, the Magus Fin. Examples of grindylow hexes include:

  • Unnamed hexes
    • Hexes used by Magi to bending space and move between objects too tight to otherwise squeeze through.
    • Hexes used by Magi and Groac'h to converse through bubbles sent thousands of miles through thaumaturgic vents.
    • A ranged space-melting hex used to melt through ships and people

Galaggi Veldt thaumaturgies[]

The Galaggi Veldt is home to numerous different nations and tribes, some of which practice unique forms of thaumaturgy. The wineherds of the veldt are able to use thaumaturgy to temporarily deform their faces as a form of entertainment, while some of the inhabitants of one of the chelona-towns use thin pipes that emit reedy notes that can drive their targets into madness. During the Iron Council's travels, they learned several techniques from the natives of the region.

  • Moss-magic - An undescribed thaumaturgy, presumably relating to the manipulation of moss.
  • Cirriomancy - An undescribed thaumaturgy, presumably relating to the manipulation of birds. It is possible that the use of Daggerpigeons by some Maru'ahmers requires cirriomancy.

Witchocracy and Firewater Straits[]

The thaumaturgy used in the Witchocracy and the islands in the Firewater Straits is not seen much in the Bas-Lag Cycle. What little is seen appears to operate on different principles than New Crobuzon thaumaturgy.

  • Hunt-sleep - A hex that is used during one's sleep, allowing the user to conjure "dream-devils" to attack foes and, in at least one case, physically carry back parts of their bodies.


  • Thaumaturgy is a term that refers to the purported ability to perform miracles. The term itself derives from the Greek word θαῦμα, or thaûma, meaning "miracle" or "marvel" and ἔργον, or érgon, meaning "work".
  • Thaumaturgy is also a transmutation spell in Dungeons and Dragons, of which China Miéville is an avid fan.