Kumamoto is Kyushu's second city, and everyone there is in a bad mood because this year's rainy season has been 'the worst in 20 years', the driver said. When the outside lane became free again, he wrenched the steering wheel to swerve out alongside his foe and show, quite unequivocally, that he was not the kind of taxi-driver who gives up his place in traffic without a fight. Especially not in the rainy season.
After the smell of burning rubber had dissipated and the driver's violent mood had passed, conversation was again possible. Who did he think was the 'strongest' for the 18 July elections? 'Hosokawa,' he growled, without a moment's hesitation.
Morihiro Hosokawa is the founder of the Japan New Party (JNP), set up as a reform party last year before the recent political upheavals, and now in a strong position to determine the formation of the next government. And with the same provincial stubbornness as the driver, although in a more subtle form, he is calling for an end to the centralisation of power in the hands of Tokyo bureaucrats. He wants some respect for Kumamoto.
Mr Hosokawa, 55, is a local hero, a direct descendant of a line of warlords who ran Kumamoto for 400 years, and a man known by everyone after eight years as the city's governor. This is where his real power is. And his popularity as a 'local name' is a reminder that Japanese politics is still run along the model of a feudal lord dispensing patronage. The issues of political re-alignment and global responsibility that academics and the media in Tokyo are keen to discuss are barely real in Kumamoto.
Mr Hosokawa's credentials are impressive. Overlooking the centre of the city is Kumamoto Castle, with soaring stone walls, cornerstones as sharp as trouser creases and overhanging eaves to fend off attackers. Built in 1607, this was his family's stronghold, and throughout the Edo era, when Japan was closed to the outside world, the Hosokawas were one of the most formidable of the clans ruling Japan.
On the campaign trail Mr Hosokawa has only half-jokingly called for a return to the old system under which warlords, or daimyo, controlled their fiefs with minimal interference from the capital in Edo (present-day Tokyo). 'Abolish the prefectures, re-establish the fiefs,' means loosening the stranglehold on power by the Tokyo bureaucracy, which is strongly resented in the rest of the country.
As governor of Kumamoto, Mr Hosokawa discovered to his fury that he did not even have the power to change the position of a bus stop by 10 yards without consulting Tokyo. Indeed, one of the main functions of a politician today is to learn to negotiate with the Tokyo bureaucracy to deliver goodies to his constituents back home. 'This must change,' said his wife, Kayoko, who has been campaigning for him locally while he co- ordinates his party's affairs in Tokyo. 'To have local power in local areas - that is our most important slogan.'
The ruling Liberal Democratic Party (LDP) knows all about local power as well, although, after 38 years of running the country, its understanding of it is slightly different from Mr Hosokawa's. In the LDP campaign headquarters Hiroyuki Matsumoto, head of the local koenkai, or political support group, said the election issues were simple. 'Number one: bring the shinkansen (bullet train) to Kumamoto. Number two: make the airport into an international airport.'
The message is that only the LDP has the clout to draw this funding out of the Tokyo bureaucracy. And political reform? 'It is a very important issue,' he said, smiling. 'But . . . the reality is . . . everyone, including us, says they are for reform . . . in Kumamoto people do not know . . . who is really for reform.'