Shugenja

A shugenja is not simply a wizard or sorcerer as Western culture understands them. They are equal parts lore-keeper and priest, with their "spells" being more akin to prayers to the elemental spirits that make up all of creation. As such, shugenja are frequently called upon to officiate many activities: everything from blessing a freshly tilled field to overseeing weddings to assisting with the birth of a child.

Spirits are everywhere, in everything, and the paltry fact that the average commoner cannot hope to understand them does not change the fact that they are integral to life and livelihood. Shugenja form the bridge between man and spirit, imparting the wishes and needs of one to the other.

In a more immediate sense, shugenja can provide occult support to more mundane activities. Their spells can raise stone walls, heal wounds, or rain fire from the heavens as they importune the kami for aid.

On the Casting of Spells
The mechanics of spellcasting are covered here, this section is more about what is involved from an in-world standpoint.

Every shugenja always has a scroll satchel on them, almost exclusively, These scrolls are the shugenja's spell repertoire; they do not memorize them and there are no "spell components" outside of some very rare instances.

The scrolls are not necessarily required to be opened and read from to cast the spell, they serve more as a focus in this regard. The information contained within the scroll is less instructions and more a contract between the shugenja and the spirits of the world (the kami), requesting that certain actions be taken by those spirits. As such, while a scroll must be taken out and brandished during the casting of a spell, it does not need to be opened, nor does the shugenja need to have the ability to read it (they must still be able to perceive any target for the spell as necessary, however).