Description:

Shouji Osamu is an elementary school teacher fresh out of college about to embark on his first day. At the school gate, he was suddenly hugged by Chise, a girl he doesn't recognize who seems to know him. He later finds out that Chise is a fifth-grade student in his class, and that she lives in the same apartment building as he does. During a late-night rendezvous, he learns that nothing about their encounter is coincidental. (Source: MangaDex)

Description:

Seven women, one man, a suspenseful harem story! During a class reunion, the school became an enclosed dimension without warning. Yelling and screaming brought no response. 26-year old unemployed Haruka Sato has to survive by cooperating with seven of his former classmates. Soon, the extreme conditions began to eat away at their sanity, and Haruka's hidden desires began to take hold. (Source: Kodansha, translated)

Description:

Ichijo Kazuya thought that he was murdered, but when he came to, he was back in his high school days. He lived his entire life as a playboy and had had countless sexual encounters with women until that fateful day that he was killed. He realizes that his murderer was his old high school friend Tanaka Masaki who was jealous of Kazuya’s relationships and his built up anger eventually exploded. Taken back 15 years into his past, it seems that he has been given a second chance at life and given a chance to make different choices. He decides that the way to prevent his eventual demise is to make sure Masaki is more successful with girls and loses his virginity before Kazuya. But fate seems to be steering Kazuya towards the path of his previous life and keeps introducing the same girls he had sexual encounters with. (Source: MangaHelpers)

Description:

Rinosuke's useless and vagrant father is now dead. Now, at the age of 16, he is completely alone and will have to quit school to survive. On the night his father dies, a naked woman with large breasts falls from the sky and lands on top of him. She introduces herself as Sakamoto Marina, the future wife of the future Rinosuke. She states that she used a time machine to come back to the past, and start a new life with the younger Rinosuke. Rinosuke's new life with his future(?) wife begins. (Source: MangaHelpers)

Description:

A spiral love story. Kouno Jun is a lively character who lives life with all his might. In kindergarten, he falls in love with Hasebe Rino, the most beautiful girl in his class, and he confesses to her. Hasebe accepts his love, but the moment she gives her answer, she vanishes on the spot. Failing to figure out what's going on, Kouno asks his friends about Hasebe, only to find out that no one remembers a single thing about her. She has just vanished, along with all memories about her, except for those of Kouno. While Kouno leads a weary and desperate high-school life, Hasebe appears again as a transfer student. However, this Hasebe is not exactly the Hasebe he knows... (Source: MU)