JAPANESE politicking is usually a gentleman affair; the stately courtesy of exchange bows and fixed smiles maintains the fiction of political consensus and party unity. But Japanese politicians were not at their best last month. The nations's general elections exploded the myth of the political gentleman and pushed long-festering political hatreds into the open. Rivals slugged it out in an unprecedentedly public breakdown of party unity, leaving the government paralyzed and the nation disgusted with its leaders' antics.

Prime Minister Masayoshi Ohira provoked this Circus Maximus by taking a gamble--one most observers thought he would win easily. He dissolved Japan's parliament, the Diet, in September, and called for a new election less than a year after his surprise victory in the last party election. Nothing recent conservative gains in local elections, Ohira saw a chance to buttress his own power with a big victory for the conservative Liberal Democratic Party (LDP), which in recent years has lost the Diet majority it had maintained through the last three decades. Ohira stumped for a tax hike to combat a growing Japanese deficit. Polls showed the LDP leading by a comfortable margin.

But when the voting ended, Ohira's gamble had backfired. Instead of a resounding LDP victory, Ohira's party actually lost a seat, bringing its total in the Diet's lower house to 248. (About 271 seats are necessary to control the key committees in the 511-member House of Representatives.) After the crapshoot, opposition parties in concert controlled as many seats as the LDP.

Ohira's blunder shattered the precarious coalition of personal allegiances that cemented the LDP. The party itself in not a unified party at all, but a composite of different factions, groups of Diet members who give loyalty first to one prominent leader, second to the LDP.

Although in previous elctions faction leaders have made token statements of support for the party leader that cloak their own maneuverings for leverage, this time the top factions heads refused to support Ohira. Instead, they called for his resignation--he complied on November 9. During that week, as Ohira fought to regain power and form a government, the Japanese public got a fascinating glimpse of the depth and breadth of political divisions within the LDP and the potential obstructiveness of the system. As the faction leaders jousted, it became clear that behind their hatred lies an issue the LDP has desperately tried to underplay: the role of corruption in the Japanese political system.

Ohira's chief rivals fought to unseat him with a passion fueled by personal enmity and ideological distaste for his alliance with Kakuei Tanaka, the former prime minister unseated after the press revealed the Lockheed airplane company's extensive bribery of government officials to gain contracts. Ohira owes much of his factional strength to Tanaka, who threw his supporters behind Ohira after being indicted in 1973. The bribery charges prohibit Tanaka from playing an active role in the LDP, but he can still play kingmaker, at least until his trial.

Both former prime ministers Takeo Fukuda and Takeo Miki have vilified Tanaka and the money politics he stands for, and they have extended their hatred to Ohira. Fukuda and Miki blame the Ohira-Tanaka alliance for depriving them of the premiership on several occasions. Miki also campaigns on a clean government plank, and has urged reforming the system of election for party president to estinguish the potential for bribery that Tanaka exploited so successfully. Tanaka in turn despises Miki as the man who jailed him in 1974 and fought to prosecute all offenders in the Lockheed case.

THESE rivalries erupted in a spectacular display of pettiness, absurdity and irresponsibility during the party elections in the Diet to determine the new prime minister. At one point, the Fukuda camp set up a blockade to prevent Ohira supporters from entering the Diet. Burly Ohira guards smashed the barrier, screaming obscenities into whirring television cameras. Ohira himself blocked Diet votes on the premiership three times, holding out to retain his power while the Diet remained paralyzed. After futile attempts at compromise with Fukuda, Ohira retained his seat by a mere 17 votes in the first runoff premier election in Japan's short parliamentary history.

With his approval rating down to 17 per cent and fellow LDP members licking their wounds, Ohira tried to restore peace by apportioning Cabinet posts among different factions. But some of his chief rivals refused to accept posts and have stated they will cooperate with Ohira only on a "case by case" basis--a precedent shattering break with Japanese traditions of party discipline. Ohira is also bound to Tanaka, who exacted a stiff fee in Cabinet posts for his key support. Among others, Ohira appointed Tadao Kuraishi, a Tanaka crony, as Justice Minister, at Tanaka's insistence.

Although Fukuda had also insisted on the appointment, which he hoped would embarass Ohira, Tanaka had other ideas, as Kuraishi soon made clear. Immediately after his appointment, Kuraishi shocked the nation by stating that the suspects were close, friends of his and he hoped they would be cleared. the prime minister is struggling to patch his party together, but still has no takers.

The bitter political infighting that characterized this election and the LDP's shrinking majority signal several political changes for Japan. The election results confirm that the LDP's salad days of dictating policy and setting the national agenda are over. Ohira needs to forge a new coalition of moderate-centrist opposition groups like the New Liberal Club, the Democratic Socialist Party and the Komeito "clean government" party to get legislation through the Diet. But working in this "period of equal balanced forces" requires wily and forceful leadership.

OHIRA and his squabbling LDP cronies have proved themselves incapable of that leadership. Their obsession with power plays and personal revenge, while hardly unusual for professional politicians, has torn their party apart. The LDP's Grand Guignol shocked a Japanese public accustomed to a veneer of unity and discretion.

Ohira's shaky political mandate also dooms his proposal for a tax hike to correct Japan's mounting deficit. The deficit, combined with a high inflation rate and a sharp drop in the yen, may have grave consequences for an already strained U.S.-Japan economic relationship. Japan has already begun to stopper its yen drain. These economic pressures will certainly curb Japanese willingness to liberalize import restrictions at a time when John Connally is bellowing about letting the Japanese sit in their Toyotas on the docks of Yokohoma. The only possible Japanese concession to American opposition prevails and cuts tax breaks for big business, special treatment that has given the Japanese companies a considerable competitive edge.

The leadership vacuum, however, may increase the responsiveness of the traditionally elite dominated Japanese political system. Without a LDP will have to bow to the pressure of opposition parties and local consumer group movements who have sharply criticized the party's emphasis on or environmental integrity. Opposition parties are already clamoring for the abolition of some of the tax breaks the LDP has granted big business.

Although Japan has prospered under the LDP, the nation has neglected some of the evils of rapid industrialization--pollution, increasing comptetition for higher education, overcrowding, inflation, substandard housing and a marked disparity in the economic security of the employees of large and small businesses. The LDP's political Ohira and his wounded party should stop playing Hatfield and McCoy; if not for Japan, for their own self-respect.