JAPANESE politicians have made the first tentative moves towards reaching a compromise over the political reforms ditched by the upper House of Councillors in a shock government defeat on Friday. But little time is left for the complicated political manoeuvres that the reform bills require if they are to be passed in some form in the current session of the Diet, which had to end on Saturday. Already there are concerns about the international implications of the political turmoil and fears that the summit between Japanese Prime Minister Morihiro Hosokawa and US President Bill Clinton will inevitably be aborted. Amid a flurry of media criticism, pressure is mounting on the politicians. The Yomiuri Shimbun declared at the weekend: ''A political system that cannot reform itself is certain to lose face in the international community. That must not happen.'' The Sunday Mainichi was even more dramatic, with an editorial that urged: ''No unprincipled deals, please!'' This referred to the widespread anxiety that any compromise reached by the politicians in an effort to get some measures passed would in effect diminish the prospects for real reform. ''We call on Hosokawa to heed two things regarding the negotiations,'' the Mainichi said. ''He should not compromise on the content of the bills. In particular, he should not accept any further emasculation of the restriction on corporate political donations.'' Corporate donations to individual politicians are banned under the failed legislation, but the former ruling Liberal Democratic Party (LDP), in blatant disregard of public opinion expressed in many polls, still insists that the proviso be deleted. This emphasises the quandary in which Mr Hosokawa is placed as he seeks to attain some degree of consensus with the LDP in the next six days. If he agrees to LDP demands, the reforms may lose meaning and he will be discredited. If no consensus is attained he will at the very least have to resign, or, at worst, call on election. In those circumstances, the economic stimulus package which the economy needs would be delayed and the summit with President Clinton would have to be cancelled. Much in fact depends upon heavy business pressure being brought to bear upon the recalcitrant LDP. There are already signs of deep business anxiety over the political situation though little has so far been said in public. Meanwhile, the first discussions took place yesterday between the coalition and the LDP concerning the many moves that will have to be made in order to resurrect reform. Today, more formal agreement will be sought to proceed in the way set out in Article 59 of the constitution. Tomorrow, the lower House of Representatives will meet to appoint a special joint committee on political reform. The committee will comprise 10 members of the coalition, nine members from the LDP and one communist. There are suggestions that one member of the 200 Socialists who either voted against or made themselves absent in the upper house vote may be added. In the following two or three days the special committee will have to reach a compromise agreeable to two-thirds of its members. Most likely any such agreement will first be attained in protracted discussions between top political leaders on both sides. The committee's consensus must be achieved in time for the House of Representatives and the House of Councillors to both pass the amended reform bills, each by simple majorities, on Friday or Saturday at the latest. The next six days in Tokyo are certain to perfectly illustrate former British Prime Minister's dictum that ''a week is a long time in politics''.