The Irregular at Magic High School, Vol. 3 (light novel) Nine School Competition Arc, Part I.

The Nine School Battle. Ever year in mid-July, students from magic high schools all over the country gather to participate in fierce competitions of magical skill. Miyuki Shiba is among the members of the team First High will send to the battle. The magical skill of the competitors will be a huge factor, but there's another one-the tuning of their CADs. Luckily, they've got someone with them who specializes in the field-Miyuki's older brother Tat...