By Chris Hogg
BBC News, Tokyo
Why does Japan's Prime Minister Junichiro Koizumi insist on visiting the controversial Yasukuni war shrine?
Mr Koizumi's visits prompt angry protests in the region
It is a question academics, politicians and pundits have argued over, without reaching any kind of consensus, since his first visit as prime minister in 2001.
It is also a question which leaders in China, South Korea and elsewhere in the region have demanded an answer to. They have been rebuffed.
And it is now a question that perhaps will become far less relevant.
Mr Koizumi visit on Tuesday must be his last as Prime Minister, before he steps down in a few weeks time.
So now there is a new question to be answered.
What kind of mess has he left for the man widely expected to succeed him - Chief Cabinet Secretary Shinzo Abe - to sort out?
Mr Abe, in his role as the government's chief spokesman, has been forced to defend Mr Koizumi's visits on many occasions.
Some analysts describe Mr Abe as a "neo-con" who is not afraid to ruffle the feathers of Japan's neighbours. His position in the race to succeed Mr Koizumi was strengthened by the hard line he took against North Korea, much to the dismay of China and South Korea when Pyongyang tested its missiles in July.
Mr Abe has been careful not to confirm or deny whether, should he be elected President of the ruling Liberal Democratic Party next month - and so, by default, become Japan's next prime minister - he would or he would not visit the Yasukuni shrine.
Many have interpreted this as a sign he is likely to follow Mr Koizumi's lead and continue visiting the shrine, thereby risking the wrath of Japan's neighbours and the paralysis in terms of the highest level inter-governmental contacts that brings.
However, others have detected an effort by the Japanese and the Chinese governments in particular to try to create an atmosphere where it would be easier for both nations to climb down from what have become polarised positions.
That might have made it easier for Mr Abe to take a different tack.
Help or hindrance
But Mr Koizumi's visit - on the most sensitive of all days, the 15 August anniversary of the end of World War II - will have made that more difficult.
The language of the recriminations flying back and forth around the region has been bitter and personal.
Some fear Mr Abe will wrap himself in the flag of patriotism
Will Shinzo Abe be able to persuade the LDP's more conservative supporters to vote for him if he is seen as climbing down in the face of such an onslaught?
The reality is he may have no choice but to try to find an elusive third way that would satisfy detractors of the shrine visits, and those who support them.
Tensions in north-east Asia are a real concern.
The threat posed by North Korea is far greater when the countries surrounding it bicker among themselves over how best to deal with Pyongyang.
Competition for energy resources, in particular between China and Japan, is also fierce.
Japan and South Korea have aging populations and falling birth-rates that will create enormous economic challenges.
So how does Mr Koizumi's successor get himself out of this mess?
His best hope will be that Mr Koizumi has in fact helped him. By visiting the shrine on 15 August he has attracted the fierce criticism that may perhaps be followed by a "cooling off" period for the new leader, a chance for rapprochement with Beijing and Seoul.
Another very Japanese approach would be to try to just ignore the problem. Not visit the shrine, but not mention it either. Pretend the problem is not there in the absence of any solution that would be acceptable to all sides.
But neither is much of an answer.
And some commentators fear that Mr Abe, who is nothing like as charismatic or confrontational as the man he hopes to succeed, might try to emulate him, to wrap himself in the flag of patriotism and continue to visit the shrine.
If that happens the prospects for continuing paralysis in Sino-Japanese and Korean-Japanese relations would be as great as ever.