Japan's finance ministry on Monday acknowledged that documents in a suspected cronyism scandal had been doctored, said a senior ruling party official, as pressure mounts on Prime Minister Shinzo Abe and his ally Finance Minister Taro Aso over the case.
The changes include the removal of a reference to a visit to the school by Abe's wife and to ties that Abe and Finance Minister Taro Aso had to a conservative lobby group, Nippon Kaigi - both well-known facts.
Without evidence of a special deal, the scandal faded and Abe was re-elected with a resounding majority late past year.
His ratings rebounded thereafter, but doubts over Mr Abe and his Cabinet have been revived with a series of fresh revelations.
The risk now for Aso and Abe, experts said, is that the suspected cover-up does more damage than the land sale itself.
Former Moritomo Gakeun head Yasunori Kagoike and his wife were arrested in July on suspicion of illegally receiving subsidies. Victory in the LDP September leadership vote would put him on track to become Japan's longest-serving premier.
If the scandal blows up, with evidence emerging that Abe was indeed involved, or his reasonably strong public approval rates plunge, he could eventually resign, though it is too early to predict that now. Critics have called for Aso to resign over the matter.
The finance ministry admitted on Monday that it had altered official documents surrounding the decision to provide an 85% discount on the appraised value of the land.
Opposition lawmakers are calling for Aso to step down to take responsibility, and some analysts believe his resignation could be inevitable.
"I deeply apologize to the Japanese people", Abe said.
"Even if Aso resigns to take the blame, that won't be enough for the public".
Prime Minister Shinzo Abe said on Tuesday that Japan wanted to see a resolution to the issue of past abductions of Japanese citizens from talks with North Korea and that North Korea must match its words with actions. He added that he hoped an investigation would "uncover the whole truth".
Abe is expected to try to keep Aso, who doubles as deputy premier, in his important finance post.
"At the very least, it seems that Aso's chances of surviving as finance minister are diminishing rapidly", wrote Tobias Harris, vice president of consultancy Teneo Intelligence, in an email.
The latest developments have already claimed the head of the National Tax Agency, who stood down on Friday.
Sagawa was head of the Finance Ministry department that oversaw the land deal, before being promoted past year to tax agency chief. But as news of the altered documents emerged, even members of Abe's own party were sceptical of the explanation that bureaucrats acted independently.
Badgered relentlessly by the opposition, finance ministry officials on Monday finally admitted that official documents had been forged a year ago.
"Unless we clarify who did this, trust for the Liberal Democratic Party will be shaken", Ishiba said.