Amakusa 1637 is a 12-volume josei manga by Michiyo Akaishi, serialized from 2000 to 2006 in Shogakukan's Flowers magazine. It follows the adventures of six Japanese teenagers: Natsuki Hayami, Masaki Miyamoto, Naozumi Yatsuka, Eri Kasugano, Seika Akishima and Eiji Horie. They're classmates from a Catholic school in Kobe, and they barely survive the Great Hanshin Earthquake of 1995; five years later, during a school trip to Nagasaki, they get mysteriously transported... to the Amakusa region in the year 1637, shortly before the historical massacre of the Christian population.
Having been transported to different years within the same timeframe, the six youngsters first must reunite with each other and assess their current situation, as well as what has changed between them. And when they're done with it and gather their common knowledge of the future, they set out to exorcise their own inner demons as well as to prevent the carnage...
Has no relation to the 1632 (Ring of Fire) series.
This manga contains examples of the following tropes:
- Action Girl: Natsuki is a Kendo expert and the sister of a Heir to the Dojo. Said abilities come off VERY handy when she's mistaken by a local swordsman.
- All-Loving Hero: Natsuki's greatest strength is her ability to unite others behind her through sheer kindness.
- Ambiguously Bi: Naozumi. He has felings for Natsuki ( which she rejects when he gives her an Anguished Declaration of Love), but is also said to yearn for Shirou.. Considering that he pretty much raped a prisioner Shirou and the Values Dissonance, he could toe into Depraved Bisexual or a practitioner of Situational Sexuality for some.
- Battle Couple: Natsuki and Miyamoto, sorta.
- Bifauxnen: Natsuki is very pretty in a boyish way. Considering she's the Body Double to a Dude Looks Like a Lady...
- Body Double: Basically, what Natsuki is to Shirou. She's at first mistaken as him, then she must keep up the charade to protect the people and avert the Shimabara Rebellion because the real Shirou is Dead All Along.
- Chronic Hero Syndrome: Natsuki, full stop. It also rubs on Miyamoto.
- Crapsack Only by Comparison: Inverted. Modern-day Japan sounds heavenly when described to 17th century persecuted serfs.
- Downer Beginning: The manga starts in 1995, with the junior-high-aged Natsuki and Masaki barely surviving the Great Hanshin Earthquake that decimated their city, Kobe. In-story, said 'quake actually was caused by the same phenomenon that would throw the kids in the past six years later.
- Drowning Pit: Matsudaira, the lord of Shimabara, has one in the grounds of his castle. At some point, both Kichou and a local girl named Yone are locked in it.
- The Dulcinea Effect: Jahn saved Seika's life when she arrived to the past and fell for her. She doesn't necessarily reciprocate, though.
- Dude Looks Like a Lady: Shirou Masuda aka Amakusa Shiro (Somewhat Truth in Television, as he was described as a very handsome young samurai).
- Gadgeteer Genius: Eiji
- Girlish Pigtails: Eri braids her hair
- HeelFace Turn: Occur frequently among those exposed to Natsuki.
- Historical Domain Character: Shiro Amakusa, Tokugawa Iemitsu, Yagyu Jubei, the Nabeshima clan, etc. Even more so: Masaki became none other than Miyamoto Musashi.
- Hooker with a Heart of Gold: Kichou is the mistress to Matsudaira, but other than that she's a very kind girl. So kind that she catches Eiji's attention and romantic interest, and they ultimately get married.
- Identical Stranger: The Bifauxnen Natsuki looks so much like Shirou that she could be his Opposite-Sex Clone, and this is a BIG plot point since the people believe her to be either Shirou or an angel that took Shirou's form to help them.
- Japanese Christian: Both the peasants and the students.
- Jidaigeki: More exactly, the Edo Period (1603-1868)
- Lovable Jock: Miyamoto and Natsuki. Both are very skilled and famous kendokas, but also are lovable persons.
- Love Dodecahedron: Natsuki loves Miyamoto. Miyamoto loves her but later is amnesiac and then he falls again for her when he gradually recovers his memories. Naozumi loves Natsuki and also Shirou, though he also saw him as a Replacement Goldfish for Natsuki since he was her Identical Stranger, and killed him in the end. Otsu saved Miyamoto whom she knows as Miyamoto Musashi and loves him too. Kinji may have had feelings for Shirou coming from their shared childhood but later redirects them to Eri. Eri kinda reciprocates Kinji's feelings but she also has a Pseudo-Romantic Friendship with Natsuki and says that, had Natsuki been a male, she would be fully in love with "him".
- Maybe Magic, Maybe Mundane: The locals believe the time-travelers to be messengers from "Deus". The time-travelers are a lot less certain, and know that their "miracles" have mundane explanations, but some of the coincidences are troubling...
- Meaningful Rename: Seika is also known as "Mariana", her Christian name. Natsuki is first referred to as "Francisco-sama" and later as Shirou. Naozumi is renamed as Kotada... and Masaki, as Miyamoto Musashi.
- Mission from God : Seika is confident the group is on one. Her confidence isn't necessarily shared.
- Mundane Afterlife: Inverted. At one point, the locals ask the protagonists to describe the "Heaven" they believe they come from. When the protagonists comply, they are themselves shocked and moved when they realize the modern society they describe - one of electric light and heating, religious tolerance, rule of law, and ample food - is, in fact, Heaven for the medieval peasants. A paradise that they'd been taking for granted.
- Saintly Church : The protagonists seem to be forming a proto-example of this.
- Set Right What Once Went Wrong : The protagonists' goal throughout the series. They succeed, resulting in a modified, apparently better timeline.
- The Strategist: Eri is the brains to Natsuki's Action Girl-like brawns.
- Student Council President: Natsuki, with Masashi as her vice-president. That is, before they get thrown back in time.
- Time Travel: The bread and jam of the story.
- Trapped in the Past: In the end, all but one protagonist remain in the 17th century. Only Eri returns to our era, finding it changed for the better by the group's actions.
- Cell Phones Always Existed: Justified; the cell phones only work when the phenomena that caused the time travel is active (allowing communication to pass through modern-day satellite infrastructure).
- Write Back to the Future: Well, more like leave sealed cell phones to be found in the future.