Its pages are filled with haiku poetry, articles on the innocent pursuit of angling and entreaties to its readers to perform good works. It sounds like a humdrum church newsletter, but the Yamaguchi-gumi Shinpo is the newly published official magazine of Japan's most powerful crime syndicate.

The magazine, which is not publicly available, has reportedly been distributed among the group's 27,700 regular members in a bid to raise morale amid tougher anti-gang laws and a slew of bad publicity surrounding the yakuza, Japan's network of influential, and violent, underworld organisations.

The Yamaguchi-gumi, headquartered in the western port city of Kobe, is still the biggest and most feared yakuza group, despite losing 3,300 members last year, according to police.

The front page of the magazine, a professionally produced publication featuring the gang's familiar diamond-shaped logo, carries a piece by its boss, Kenichi Shinoda, instructing younger members to observe traditional yakuza values, including loyalty and discipline.

The magazine's publication, which was reported by the Japanese media, comes soon after an apparent end to a damaging seven-year turf war involving other yakuza groups on the southern island of Kyushu, in which innocent "civilians" were among the victims.

"The problems in Kyushu reminded people that the yakuza can be violent and disruptive," said Jake Adelstein, an expert on the yakuza and author of Tokyo Vice, a memoir of his stint as a crime reporter in the Japanese capital.

"The magazine is the Yamaguchi-gumi's attempt to show the public that it's an old organisation that upholds traditional Japanese values; that its members are not a bunch of violent thugs like those guys down in Kyushu.

"It has sent the magazine only to regular members, but it knew that the details would leak out."

In his column, Shinoda concedes that new anti-gang laws have made it harder for the group to make easy cash. Although membership of the yakuza is not illegal, the gangs' activities are. They are deeply involved in extortion, payday lending, racketeering and blackmail, but have recently moved into white-collar crime, setting up front companies in an attempt to survive.

"They may feel that it has become harder to carry on with their activities under anti-mafia ordinances that bar them from opening new bank accounts and signing real estate contracts," the Mainichi Shimbun quoted a police source as saying.

Pressure on yakuza finances intensified last year when the Obama administration said it would start freezing the Yamaguchi-gumi's US assets and ban it from conducting business in the country. The move came after the US treasury department said the group was earning billions of dollars through drug dealing, human trafficking, money laundering and other cross-border activities.

Last year total membership of the yakuza stood at 62,300, down 7,100 from the previous year, according to the national police agency. The Yamaguchi-gumi accounts for about 40% of the total.

The magazine may not succeed in recruiting members, but it at least offers light relief to those already leading lives of crime. Along with senior members' diaries of recent fishing trips, there is a section devoted to satirical haiku and pieces on the strategic board games of go and shogi.

Newly introduced penalties for individuals and firms that associate with crime groups have hit the once-thriving market in yakuza fanzines, and manga comics detailing the exploits of notorious gangsters have become far less visible on bookstore shelves, said Adelstein. "With yakuza PR fading, this magazine looks like an attempt to fill the gap," he said.