Iwamoto-senpai no Suisen is a Manga/Manhwa/Manhua in english language, military series, english chapters have been translated and you can read them here. You are reading chapters on www.mgeko.cc fastest updating comic site. The Summary is

Manga centers on a military academy middle school student named Iwamoto, tasked by his headmaster to investigate the Donji Festival in the town of Shikibe, with the goal of ascertaining whether the town's "Shining Miko" is merely a trick or real.