TOKYO - The act of jigiri is seen as honourable in the yakuza world, where minions conduct crimes on behalf of their gang bosses and take the fall for them.

This comes with "prizes". If they get caught, the yakuza will hire and assign a trusted lawyer. If they get jailed, the well-being of their family is guaranteed. Upon release, the gang member is fast-tracked to an executive position.

This was likely the case when a member of the Kudo-kai - whose don Satoru Nomura, 74, was sentenced to death on Tuesday (Aug 24) - was released from jail in Kumamoto last November.

Reports said the gangster in his 40s was escorted by suspected members of the Kudo-kai when he came out after 19 years in jail for the 2001 murder of a man who had left the gang and refused orders to return.

Yet he would be returning to a very different Kudo-kai, which appears to be in decline, from a peak of 1,210 members in 2008 to 430 members last year.

Its woes have deepened to the extent that it had to sell off its headquarters building in the port city of Kitakyushu in Fukuoka prefecture in February last year.

The Kudo-kai is not alone in what appears to be the terminal decline of the yakuza.

The lustre of the yakuza has waned in recent years amid tougher legislation and lower social tolerance. Nationwide, the number of yakuza mobsters shrank to a new low of 25,900 last year, data from the National Police Agency said.

This was down nearly 70 per cent from the 80,900 members in 2010.

The yakuza is said to have roots in the Edo period of Japanese history, when the lowest social groups and outcasts like the burakumin caste formed organisations of their own as a mirror society to the affluent.

In post-war Japan, these offered a sanctuary for the aimless in a society divided by a yawning rich-poor gap, their ranks swelling with romanticised ideals of belonging and brotherhood.

They have long been regarded as semi-legitimate organisations, with registered offices and rumoured ties with influential politicians and business leaders. They have even channelled their riches into disaster relief efforts.

But they exist in a grey zone. Japan has never banned the yakuza outright, and has long co-existed with these "antisocial forces" by refusing to clearly define them.

Controversy swirled around former prime minister Shinzo Abe in 2019 when tabloids reported that a suspected yakuza member had been on the guest list of taxpayer-funded cherry blossom viewing parties.

Meanwhile, it is an open secret that the yakuza dabbles in nefarious businesses such as drug and sex trafficking, runs illegal gambling dens, and has its hand in fraud, robbery, assault and various other crimes.

Even with the reduction in yakuza numbers, violent turf wars continue in modern-day Japan.

The police are closely watching two gangs: the Yamaguchi-gumi, whose 8,200 members make it Japan's largest yakuza syndicate; and its splinter group Kobe Yamaguchi-gumi, which broke away in August 2015 and now has 2,500 members.

In November last year, two men believed to be with the Yamaguchi-gumi shot down two members of the splinter group in public.

In response, police have designated six cities in western Japan's Hyogo prefecture as under "special precautions". This allows the authorities to haul in suspected gang members for having an illegal assembly of five people or more, or for loitering near their rival's compounds.