TOKYO - The Japanese government's initial failure to disclose information on a sweetheart land deal at the centre of a 2017 cronyism scandal that ensnared Prime Minister Shinzo Abe was illegal, the Osaka High Court ruled on Tuesday (Dec 17).

An assembly lawmaker of Toyonaka city in Osaka prefecture, in raising the case, questioned the constitutionality of its initial refusal to disclose the cost of state land sold to the right-wing school operator Moritomo Gakuen, which had ties with Mr Abe's wife Akie.

The verdict comes as Mr Abe's approval ratings are on the slide amid another controversy, this time over whether he wined and dined voters at a taxpayer-funded sakura (cherry blossoms) spring garden party to reward voters from his constituency in Yamaguchi prefecture.

Again, questions are being raised about the government's sketchy black-box management of public records, with the guest list shredded hours after a request for the document was put in by the opposition.

A Kyodo News poll said 83.5 per cent of respondents did not buy Mr Abe's explanations on the garden party, while another by Sankei Shimbun and Fuji News Network said 74.9 per cent were unconvinced.

All this has fed into fervent talk over whether Mr Abe will call a snap general election to consolidate his mandate and catch a divided opposition off guard, as he had done under pressure in 2017. An election is only due by October 2021.

The traditional sakura event - held for VIPs like diplomats, businessmen and athletes - has been called off next year amid scrutiny of its ballooning budget and opaque invitation procedures.

The number of participants, supposed to be capped at about 10,000, has risen to 18,200 this year. The budget has also nearly doubled to 55 million yen (S$680,600) this year from 30 million yen in 2014.

The opposition has accused Mr Abe of using public funds to pay for package tours for the voters to attend the sakura event and a dinner party in Tokyo.

Participants of the dinner party were charged just 5,000 yen - way below the market rate of 11,000 yen.

But Mr Abe has said that "all travel and hotel expenses, including the dinner party, were paid out of pocket by the participants themselves".

While no hard copy of the guest list is apparently available, the government claims there is no back-up soft copy that can be easily retrieved. And even if it could, the government says that it would be improper to disclose the list out of privacy considerations.

Domestic media are drawing parallels to how documents were likewise discarded or doctored in the Moritomo Gakuen scandal.

State land had been sold at just one-seventh of the appraised value to the operator, which wanted to build a new elementary school with Mrs Abe as its honorary principal.

"The discarding of the list has deepened suspicions that the administration of Prime Minister Shinzo Abe is operating the public record management system arbitrarily," the Mainichi Shimbun said in an editorial on Monday.

"The Abe administration has made something of a habit of discarding public documents at the heart of malfeasance allegations. The same thing happened with documents relating to the heavily discounted sale of state land to Moritomo Gakuen," it added.

While the government first said that documents regarding the land deal were trashed, it later released a trove of records - some of which were doctored to scrub the names of Mr and Mrs Abe and other politicians.

The Moritomo Gakuen scandal was closely followed by another controversy involving educator Kake Gakuen, where Mr Abe was alleged to have favoured a bid by a close friend to open a veterinary school.

As his support plunged in the wake of the two scandals, and despite having said he was not thinking of a snap election then, Mr Abe went ahead with one in October 2017 that his ruling Liberal Democratic Party (LDP) won handily.

He is also due to step down as LDP chief in September 2021 after serving an unprecedented three straight terms.

But LDP bigwigs like secretary-general Toshihiro Nikai and Finance Minister Taro Aso are backing Mr Abe to stay on beyond 2021, given that Japan's stability is gaining eminence in global geopolitics.

Already, Mr Abe has stirred speculation that a snap election may be imminent, telling a news conference last week: "If I find that the time has come to seek public judgment, I won't hesitate to dissolve the Lower House and call a general election."