No, it's not a Zen koan. But given the difference between what most westerners think of as a bath and the ritualistic experience associated with the Japanese ofuro, it might as well be.

Many visitors and foreign residents in Japan approach the nation's traditional baths with a mixture of trepidation and curiosity. Bathing at home or in a hotel room is a mini adventure for newcomers. Most have heard that taking a bath in Japan entails rather more than sitting in a long, rectangular tub and splashing a little tepid water around in order to get clean. Some might have learned that they should wash before hopping in. But the surroundings are still unfamiliar - short, deep unit baths, sometimes a toilet in the same small space, and not a shower curtain in sight.

Sticking to the shower is an option. But when curiosity or cold winter temperatures finally get the better of you, it's tempting to find out why countless Japanese TV shows and tour companies are dedicated to bathing. You run a deep, steaming bath, and, after washing, ease your way into the hot water. Your skin first tingles and then feels numb with the heat. Wiping a little perspiration from your brow, you grow accustomed to the temperature and begin to wonder what all the fuss is about.

Then, hauling yourself up and stepping out of the tub, you realize that your legs have gone to sleep. Your muscles are looser than they have been in years. You're craving liquid refreshment, and understand for the first time why the denizens of Japanese beer commercials make that peculiar "Aaaahh!" sound as they swig a cold one with an onsen visible in the background. Ten minutes later you feel invigorated and more inquisitive than ever about the mysterious rejuvenating qualities of heated water.

Personal experiments are fine, but communal bathing is a different ball game. Most Europeans and North Americans have bared some bits at the beach, but getting naked with a bunch of strangers for the purposes of relaxation is anathema to those raised with Christian mores. Once the initial awkwardness has been overcome, however, the world of sento and onsen will provide some of your most memorable experiences in Japan.