Included with seventh volume of the Asobi Asobase manga.

Disillusioned with the afterlife, a new student causes a scene during a classroom test and expresses his doubts about whether getting good grades can really lead to escaping the school and ascending to Heaven. Afterwards, he is confronted by the new student council president—a familiar face whose past experiences give him powerful insight into the true nature of the school and first-hand knowledge regarding the futility of rebellion. [Written by MAL Rewrite]

Episode 13 of Acchi Kocchi that was included in Vol.6.

Mirai, an improved Kongou-class Aegis guided missile destroyer, is one of the newest and most advanced ships in the entire Japanese Self Defense Force (SDF). Her crew, also one of the newest, is lead by Capt. Umezu Saburo and Executive Officer Kadomatsu Yosuke. While running scheduled training exercises one day, Mirai encounters a fierce storm that throws their navigation systems into temporary disarray. After a few minutes of recovery, the crew is shocked to discover that they've been transported back in time to June 4, 1942—The Battle of Midway, during World War II. Letting history take its course for this battle, they manage to avoid the conflict firsthand and make a vow to remain anonymous, changing history as little as possible. However, when the crew comes across the dying Lt. Commander Kusaka Takumi, XO. Kadomatsu's instincts to save lives takes over, changing the course of history more than he could've imagined.