An anonymous Hacker News contributor posted a step‑by‑step account of what happens after a person is detained in Japan, in the country. Arrests for minor offenses—public arguments, unpaid items, visa overstay, or even borrowing an umbrella—can quickly lead to placement in a police‑run kōchi‑sho. Unlike a courtroom, the facility serves as a holding area while investigators build a case.

Detention can last up to 23 days for a single arrest before formal charges appear. The period starts with three days of processing, followed by a ten‑day window that prosecutors may extend another ten days. Authorities can reset the clock with additional allegations, meaning some detainees remain confined for months, often enduring harsh schedules, limited showers, and constant surveillance designed to wear down resistance.

Compared with the United States, where suspects see a judge within days and can post bail, Japan’s system emphasizes pre‑charge interrogation and strict routine. Detainees receive only Japanese‑language instructions, must purchase toiletries, and cannot keep personal items, even basic underwear. The contributor warns that such pressure frequently produces false confessions, leaving individuals with lasting psychological trauma and disrupted livelihoods after release.