Although modelled on the swordsmanship of the old samurai, kendo has become considerably tamer in its reincarnation as a sport/martial art. Far from promoting aggression and physical assertiveness, it focuses on mental concentration and graceful movement, and most of the kendoists are ordinary office-workers from close by who enjoy the exercise and the chance to relieve some work-related stress.
After the practice sessions, on Tuesdays and Thursdays, often a group will head off to one of the numerous small, noisy restaurants that crowd around the train station. Food and drink is consumed, jokes are told and people relax together in a way that their strictly hierarchical work environment does not allow.
Last week, in the changing room of the gym, someone announced they were going to 'Kinpai', the Golden Drinking Cup, a restaurant which serves fish exclusively. 'When you taste their tuna belly sashimi (raw strips of the most tender part of the tuna), you won't want to eat it in any other restaurant,' I was assured.
Kinpai was nearly full when we arrived: four tables along one wall, and three along the other, with a small space between for the obasan (honourable grandmother) and her daughter to squeeze through with plates of fish and trays of drinks. On this steamy hot August evening, the door was open to let in what little breeze there was and to let out the clouds of cigarette smoke. Most of the customers were salarymen, letting off some steam with colleagues before the long train journey home.
The weather provided the customary opening to conversation, as it does everywhere, at all times and in every situation throughout Japan. This year's heatwave has been particularly unpleasant: water rationing has been imposed in many parts of Japan, and the only good thing anyone around the table had to say about the hot weather was that it has prompted discount shops to import foreign beer costing nearly half the price of Japanese brews.
With its heavy protective clothing and mask, kendo produces a heavy sweat at the best of times - and with no air conditioning in the practice hall, this summer has been almost unbearable. One man said he remembered a similar heatwave some years ago: 'One of the older kendoists collapsed from dehydration. He had to be taken to the hospital and given an intravenous drip.'
By now thirsts were being liberally quenched with bottles of cold beer, and the tuna belly was indeed very good. The company hesitated over whether to switch to sake (Japanese rice wine) but with liquid replacement still a priority, beer won the group's consensus.
Someone started an anecdote about Antonio Inoki, a professional wrestler who was elected to the Upper House of Parliament in a somewhat comical campaign. He had been sighted in a bar recently, with his jacket off and sleeves rolled up, threatening to rearrange the anatomy of another patron who had insulted him. But it turned out the two were both posing, and no real violence ensued. 'As in the wrestling ring, so in real life.'
Various dishes of squid, yellow-tail and shellfish appeared on the table - the honourable grandmother had taken it on herself to choose what we were to eat. After all, she knew best which fish was the freshest in the kitchen.
Before we left, a discussion somehow arose over the virtues of the ancient Romans, who were, I was assured, very similar to the Japanese. 'The Romans had little power as individuals, but they had good organisation, so they were very powerful together.' But apparently Julius Caesar was the ruin of this system of consensus, trying to amass too much power for himself: the same thing happened in Japan before the Second World War, 'and could easily happen again', it was muttered darkly.
But the bill had arrived, and there was much hilarity as the accountant among us, red-faced from drink, tried to work out in his mind how much each one owed. He gave up in inebriated confusion, paid the whole bill himself, and handed the receipt to his neighbour to do the calculations. And then the whole group bowled out on to the street in the direction of the station, as another day in Tokyo came to a laughing, comradely, slightly drunken end.