On 3 March 2008, Shibuya Channel’s People | Close-Up series sat down with Koichi Kariatsumari (狩集 紘一) — a Kagoshima-born former Metropolitan Police officer who spent more than four decades on the force, worked Shibuya early in his career, and later wrote the memoir 《警視庁捜査第四課○暴刑事(デカ)》 (Metropolitan Police Investigation Division 4 — Anti-Gang Detective) for Otowa Publishing.
The installment marked the 30th Close-Up feature. After months of artists and shop owners, the editors chose a retired police chief whose story argued that today’s youth-facing Shibuya only exists because earlier decades of street enforcement made the ward walkable again.
Why he became a detective
Asked why he entered detective work, Kariatsumari traced the decision to Shibuya itself. He entered the Metropolitan Police in 1962, started at Shibuya Police Station, and watched organized crime pressure the ward’s public space. That experience, he said, made him want to become an anti-gang detective — an ōbō deka — and answer citizen expectations for enforcement. “Shibuya is the town that gave me the chance to become a detective,” he told the interviewer.
Why the book exists
Division 4 had been founded in November 1958 as a specialist anti-gang unit — later romanticized as the “flower of Investigation Division 4.” Kariatsumari rose through its ranks. When organizational reform renamed the unit the Organized Crime Control Division 4, he wrote the book as a message to younger detectives: pass on Division 4’s investigative spirit and keep fighting organized crime.
Writing was harder than filing reports. Gathering materials took time; after submitting the manuscript he underwent cancer surgery lasting more than 15 hours, then corrected proofs through pain. Privacy rules also forced careful clearance with people named in the narrative.
What he wanted readers to notice
Senior colleagues told him they missed the old Division 4 name but recognized the book as a useful transmission of that culture. For the public, he hoped readers would see the hardship behind quiet public-safety work, the seriousness of anti-gang investigation, and family love running underneath it. For younger detectives, he offered the book as a reference for how to live the job.
Work itself, he said, had been about “a man’s romance” and “realizing social justice.”
After retirement
Kariatsumari retired in 2003 with a Superintendent-General’s merit award. Looking ahead in 2008, he planned to keep fighting cancer while advising on countermeasures against antisocial forces — gangs, sokaiya, fake dowa and uyoku pressure groups, corporate and newspaper thugs — as a citizen-side ASF adviser.
The editors closed by noting how unusual it was to hear a former station chief frame Shibuya’s current youth street as something that had to be hard-won after rougher public-order years.
Book details from the page
- Title: 警視庁捜査第四課○暴刑事(デカ)
- Author: Koichi Kariatsumari
- Publisher: Otowa Publishing (音羽出版)
- Published: July 2007
- Price (listed): ¥1,575
- Publisher phone (historical): 03-5807-7037
For the street layer that detectives once treated as a public-order problem and shoppers now treat as a destination, the Shibuya Crossing live camera still reads basin density in real time. Readers connecting Close-Up history to today’s feeds can start with how to watch Japan live.
