Ken yo, Kaku Katariki ~ ken to Mahō no Isekai ni Tensei Shita noni Jitsu wa Bunmei ga Gendai Reberu Datta ken

This is the story of a man who was reincarnated into a different world (Not a medieval fantasy). He was reborn into a world of swords and sorcery and was taken in by an old man who was training in the mountains. The protagonist found joy in mastering the art of the sword and ended up spending over a decade secluded in the mountains. After the old man passed away, Yukito, who was now alone, made the decision to descend the mountain. However, he came to realize that in fact, there were cars and cell phones, and the civilization was at a modern level. Even though it was a world with both swords and sorcery there were no Demon Lords or Heroes. Having modern knowledge as a cheat? What is that?...