Shinobu Tsukasa

Shinobu Tsukasa, born Kenichi Shinoda, became the sixth-generation boss of Yamaguchi-gumi in 2005.

His tenure sits at the center of the most important modern transformation in Japanese organized crime: the rise of the Kodo-kai power bloc, intensified police pressure, and the 2015 fracture that produced Kobe Yamaguchi-gumi.

From Kodo-kai to the top

Tsukasa's rise cannot be understood without Kodo-kai.

The Nagoya-based organization became one of the most influential affiliates inside Yamaguchi-gumi. Tsukasa helped build that power base before reaching the top of the parent syndicate.

His elevation in 2005 therefore represented more than the arrival of a new boss.

It shifted the internal center of gravity.

Older Yamaguchi factions had deep roots in Kobe and in organizations such as Yamaken-gumi. Kodo-kai's growing influence created a competing bloc with its own leadership network.

Police focus on Kodo-kai

Japanese authorities increasingly treated Kodo-kai as a priority.

The National Police Agency described it in the early 2010s as effectively controlling Yamaguchi-gumi and as a driving force behind the larger syndicate's power.

That assessment matters because it shows that the later internal dispute was not merely a personality conflict.

It concerned the distribution of power inside Japan's largest criminal organization.

Imprisonment

Tsukasa served a prison sentence after a firearms conviction and was released in 2011.

The imprisonment did not end his status as Yamaguchi-gumi boss.

Instead, senior figures continued to manage the organization within its established hierarchy.

One of the most important was Kiyoshi Takayama, another key Kodo-kai figure who became a major power inside the sixth-generation leadership.

The 2015 break

In August 2015, thirteen direct bosses left Yamaguchi-gumi.

They formed Kobe Yamaguchi-gumi under Kunio Inoue.

The breakaway included powerful organizations with long histories inside the parent syndicate, most notably Yamaken-gumi.

Public accounts of the split emphasized dissatisfaction with the concentration of power around the sixth-generation leadership and the Nagoya/Kodo-kai bloc.

For the archive, this means Tsukasa's biography is inseparable from the organization article and the split event article.

Conflict after the split

Japanese police documented repeated confrontations between Yamaguchi-gumi and Kobe Yamaguchi-gumi after the separation.

The violence included shootings and vehicles driven into rival offices.

Authorities eventually classified the rival groups under mechanisms designed for organizations engaged in serious conflict, increasing restrictions around offices and activity.

The confrontation has persisted long enough to become one of the defining stories of twenty-first-century Japanese organized crime.

Fragmentation of the opposition

Kobe Yamaguchi-gumi itself later split.

Yoshinori Oda formed the organization that became Kizunakai. Ikeda-gumi also became independent. Yamaken-gumi, historically one of the most powerful components of the breakaway, underwent another realignment.

This fragmentation altered the strategic picture.

The 2015 revolt had initially presented itself as a substantial challenge to Tsukasa's leadership. Over time, the opposition divided into multiple organizations.

Tsukasa's place in Yakuza history

Earlier Yamaguchi-gumi generations are often associated with expansion and succession wars.

Tsukasa's period is different.

His era is defined by the tension between internal consolidation and external contraction.

The organization remained extraordinarily important, but the entire bōryokudan population was declining under sustained legal, financial and social pressure.

At the same time, the largest syndicate in Japan fractured into competing descendants.

That combination makes Tsukasa one of the most consequential modern bosses in the the archive database.

The surrounding network

A complete Tsukasa page must connect to Kodo-kai, Kiyoshi Takayama, Teruaki Takeuchi, Yamaguchi-gumi, Kunio Inoue, Kobe Yamaguchi-gumi, Yamaken-gumi, Kizunakai, Ikeda-gumi and the 2015 Yamaguchi-gumi Split.

It should also point backward to Kazuo Taoka, Masahisa Takenaka and Yoshinori Watanabe, because Tsukasa inherited an organization shaped by their generations.

The story is therefore larger than one gangster.

It is a story about how control of a sprawling criminal federation shifted geographically and institutionally—and how that shift fractured the federation itself.

Sources

– [Japan National Police Agency — 2025 White Paper, Boryokudan situation](https://www.npa.go.jp/hakusyo/r07/honbun/html/bb4421000.html) — Official NPA overview; 25 designated groups as of June 1, 2025 and major-group concentration. – [Japan National Police Agency — 2017 White Paper, Measures against Organized Crime](https://www.npa.go.jp/hakusyo/h29/english/full_text_WHITE_PAPER_2017_E.pdf) — Official English-language background on membership decline and the 2015 split. – [Japan National Police Agency — 2016 White Paper, Yamaguchi-gumi / Kobe Yamaguchi-gumi](https://www.npa.go.jp/hakusyo/h28/honbun/html/st500000.html) — Official account of 13 direct bosses leaving Yamaguchi-gumi and forming Kobe Yamaguchi-gumi. – [U.S. Department of the Treasury — Targets New Yakuza Syndicate](https://home.treasury.gov/news/press-releases/jl0694) — Official sanctions release describing Kobe Yamaguchi-gumi, Kunio Inoue and Osamu Teraoka. – [Japan National Police Agency — 2013 White Paper, Yamaguchi-gumi situation](https://www.npa.go.jp/hakusyo/h25/honbun/html/p3110000.html) — Official background on Yamaguchi-gumi dominance and Kodo-kai influence.