Magecraft & Curse

Technology used by Ciel and Roa. Known as magecraft—spatial interference and application methods based on rituals (systems).
Magecraft can be used by just about anyone with enough training, but the potency depends on the individual’s own qualities (the number and quality of their Magic Circuits).
In the story of Tsukihime, runes, kabbalah, curse, witchcraft, wonderworking, etc, are all bundled together as magecraft. Xian arts and esoteric buddhism are also included in this category, but as they’re part of a different faction, they’re not brought up in Tsukihime.
Magecraft is basically all-purpose, however, it cannot make the impossible possible.
At the end of the day, magecraft is a technique for abbreviating the processes of methods already possible to the individual themselves.
Even if there was magecraft that allowed one to go to the moon, it would still require preparation with costs on par with—or even exceeding—that of actually creating a rocket.
“Sure, it’s amazing being able to shoot fire from one’s hands—but nothing more than just amazing. If all you wanna do is shoot some fire, wouldn’t it be more efficient to just bring a blowtorch?”
This is the simplest explanation you can give regarding magecraft in TYPE-MOON lore.
You could say that magecraft is something which modern science can substitute for.
But you could also say that magecraft can substitute for science.
Separate from magecraft, there’s that which can perform things impossible to realize through modern human technology, called magic.
By the time of Tsukihime’s story, there are only five things which can still be called magic.

Katatuki Kouhon: World & Tsukihime Character Setting