The web site of bingus-my-beloved

Bungō Stray Dogs Timeline

BSD is probably my favorite manga ever, but the timeline is devilish and slippery as an eel, so the last two times I've reread it I've noted down any dates I could find, and tried to piece together a coherent timeline. This is the result of that.

I’m considering Dead Apple and BEAST canon for this, but I try my best to only rely on them as further support for things already mentioned elsewhere.

If a year has multiple events, I'll be listing the earliest events last . If I don't know when an event happened in a year relatively, I'll put it in brackets.

2000:

I think it's stupid and futile to try and line up BSD with the real world temporally—as in, to try and line up the events with any real world date—because the world is so clearly different from ours that it's not even really applicable. I use 2000 here arbitrarily as the start of the main manga because it's easier and more organized to use dates than to say, like, "when this character was 15". I chose specifically 2000 just because it's an 'easy' year, the millennium.
The start of the main manga must happen sometime between January and October of 2000. There's a discrepancy in Fukuzawa and Ranpo's ages. In Untold Origins, Ranpo is 14, while Fukuzawa is 32 (18 year age difference). Meanwhile, in modern day, Ranpo is 26, while Fukuzawa is 45 (19 year age difference). Since Fukuzawa's birthday is before Ranpo's, the only explanation I could think of for this is that Ranpo was born in 1973, and that his birthday hasn't passed yet in 2000.
Since he's in most of the light novels, I use Dazai's age to date most of them, so for reference: he's 22 in modern day.

1999:

Kyōka likely joined the Port Mafia in 1999, as it's stated in Chapter 49 that she met Akutagawa six months ago.

1998:

It's directly stated that Dazai is 20 in the book.
Also stated in its own and Dark Era's afterwords that the novel takes place two years before modern day.

1997:

[Chapter 43 states that Kyōka's parents were killed, and the ability Demon Snow was passed onto her three years ago.]

[Chapters 74.5 and 75 state that Sigma was born into existence from the Book three years ago.]

1996:

It's mentioned in the afterword that the novel takes place four years before modern day.
In Chapter 51, Dazai mentions that Akutagawa hasn't been under his command in four years.
In Chapter 70, Ango mentions that he erased Dazai's mafia crimes four years ago.

1995:

Akutagawa joined the mafia
The short story mentions a few very important things, 1. Dazai was made an executive the same day he picked up Akutagawa 2. Dazai is not more than a year older than Akutagawa at the time. Meanwhile, BEAST further explains that the main story is four and a half years from when Akutagawa & Dazai met. Modern day Dazai is 22, while Akutagawa is 20, and their birthdays are June 19th and March 1st respectively. Therefore, The Heartless Cur & Dazai's promotion to an executive can be pinned down to specifically early/mid 1995, after March but before June. Dazai would be 16, and Akutagawa 15.

1994:

Dead Apple states that it happened six years before modern day.
Must be after Stormbringer because Chūya uses Corruption in it.

TBA

The book directly states that Chūya is 16 years old.

[Chapter 92.5 states that Jōno was recruited to the Hunting Dogs by Fukuchi six years ago.]

1993:

Self-explanatory

1992:

It's stated in Fifteen that Dazai was 14 when he was an accomplice for Mori's murder

[In Chapter 88, Bram states that he was imprisoned by Fukuchi eight years ago, however I don't exactly trust Bram's perception of time.]

1991:
N/A

1990:
N/A

1989:
N/A

1988:

This was when Mori retrieved Yosano from where she had been staying after the Great War. Mori wanted to take her back to continue his plan of an immortal regiment, and Fukuzawa could not approve of this—thus ends their alliance. The two fought and Yosano joined the newly-formed agency. (per Chapter 66)

After Untold Origins, Fukuzawa sought to found the Armed Detective Agency. Natsume tasked Fukuzawa with guarding Mori, an underground doctor who was looking to assassinate the current mafia boss. Having the two meet was part of Natsume's Tripartite Tactic. (per Chapter 49)

[Chapter 115 states that when she was only a few months old, Teruko used her ability to age herself up in order to work as a partisan. She was nearly killed, and was taken in and recruited to the Hunting Dogs by Fukuchi.]

1987:

Must have happened late 1987, see my explanation up in 2000.
Additionally, Oda is still active as an assassin in Untold Origins. He's 23 in Dark Era, where he mentions he met Natsume & stopped killing at 14.
In Chapter 82, Fukuchi also states that Ranpo and Fukuzawa met thirteen years ago, not twelve.

1986:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1985:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1984:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1983:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1982:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1981:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

1980:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.

??:
Lorem ipsum dolor sit amet, consectetur adipiscing elit, sed do eiusmod tempor incididunt ut labore et dolore magna aliqua. Ut enim ad minim veniam, quis nostrud exercitation ullamco laboris nisi ut aliquip ex ea commodo consequat. Duis aute irure dolor in reprehenderit in voluptate velit esse cillum dolore eu fugiat nulla pariatur. Excepteur sint occaecat cupidatat non proident, sunt in culpa qui officia deserunt mollit anim id est laborum.