AS the complex wheeling and dealing which will eventually produce a new Japanese government gets underway, there are only two certainties. First, the process is bound to be protracted. Japanese consensus building of any kind is always slow. But an additional complication is the start tomorrow of the trial of former Liberal Democratic Party kingpin Shin Kanemaru on charges of massive tax evasion. Damaging details are expected to emerge during the trial, discrediting other leading LDP figures. In these circumstances, none of the opposition parties which might consider alliance with the LDP are likely to give any sign of interest, let alone make a commitment. This might give the edge to the eight opposition parties in their coalition-building, except for the fact that the main potential architect on the opposition side, Shinseito leader Ichiro Ozawa could, as a former Kanemaru protege, also be affected by thetrial's disclosures. The second certainty is that while the ''smoke-filled back rooms'' are bound to see a lot of the action, the political manoeuvring will be more open than ever before. The greater use by politicians of television talk shows, and television's inclination to put on lengthy political specials, are two of the ways in which Japanese politicians are being more open about their views. When voters tell their MPs before millions of viewers that they did not vote for them so that they would quickly jump into bed with the LDP, such openness is likely to make coalition building even more extended. The increased political animation is significant, even revolutionary, but for now, the smoke-filled back rooms will still probably win out. In this sense, Prime Minister Kiichi Miyazawa has performed a service by staying on, despite the calls for him to go. By remaining as caretaker he can at least allow the effort to get a new government with a majority to go at its natural pace. Were he todepart, he would probably create a vacuum which might not be easily filled.