Amid the current national craze over anything that might boost brainpower -- or at least help its legions of elderly to retain their mental functions -- a relatively low-key, centuries-old Buddhist practice has lately been attracting a lot of attention.

In fact, shakyo -- copying Buddhist sutras by hand -- has been shown to be effective in preventing dementia, according to a recent study by Tohoku University Professor Ryuta Kawashima and the major publishing house Gakken Co.

Kawashima, who is Japan's top brain expert, measured the cerebral activity of a sample of senior citizens in Sendai by fitting groups of them with sensors on their heads to monitor changes in their brain's blood vessels. In some 1,000 tests of participants, the study found that when the subjects were writing out sutras by hand, their brains became more active in certain areas than when they were performing any of 160 other tasks, including rolling walnuts in their palms, doing cat's cradle or sticking pieces of colored paper onto pictures.