Another Stupid Isekai - Chapter 22

After breaking up with his girlfriend, he accidentally acquired a genius system and rose from there against the heavens, becoming invincible..

- Description from Novelupdates

After being transported to this world, Nara Kazuki discovered that as long as he grinded enough proficiency, his jutsu could level up.And so, he began walking a very... peculiar ninja path.

What the hell? That menace who bullied me since I was six years old, actually became a pretty girl after three years of living apart? And she even ran to our agreed duel location to confess to me, hoping that I can become her boyfriend?!

Transported to a rural family in 1973, where eating required food stamps, dressing needed cloth tickets, stepping out asked for a letter of introduction, doing business was considered speculative profiteering, and securing a job demanded an urban household registration. She, a young girl from the countryside, faced an indifferent mother, a troublesome younger brother, and an elder sister who often had poor ideas. Life had become insufferable.Memories from her past life are mostly forgotten, yet the myriad of objects in her magical storage ring baffles her greatly.