Kouritsu Kuriya Madoushi, Daini no Jinsei de Madou o Kiwameru効率厨魔導師、第二の人生で魔導を極める (Japanese); Kouritsu Kuriya Madoshi, Daini no Jinsei due Madou wo Kiwameru; The Mage Will Master Magic Efficiently in his Second Life (English)

From /ak/ scans: Zeff Einstein spent his whole life mastering red magic and was finally recognized for it, yet a new spell that was soon created revealed that his talent for red magic was his lowest. Bitter at the thought of all his wasted effort, he creates a spell to send his old self back in time to his younger body and together with the determined "genius" mage Milly and the handsome swordswoman Claude, he intends to master magic more efficiently this time.