In the minds of many people, religious rivalry could occasionally be expected to  spill over into violence in places as diverse as the occupied West Bank or Glasgow's 'Old Firm' football derby.

Japan's Kansai region, home to the world's most renowned Zen gardens and some of the country's finest cuisine, on the other hand, is not generally seen as a tinderbox of religious tension.

But over the last year a series of mysterious attacks on Protestant churches and other facilities have roiled the area, leaving many churchgoers shaken and perplexed.

JAPAN-CHRISTIANS/

There have been over 50 such incidents in the last 12 months, the Asahi Shimbun newspaper reported, all involving fire extinguishers being thrown through the windows of Protestant premises when nobody was inside. Although there haven’t been any injuries, NHK news last week showed parishioners saying the attacks were shocking and unsettling.

Perhaps the most unnerving element of the incidents is that nobody seems to have any idea who’s carrying them out, or why. Although the fact that no attacks on Catholic or Buddhist premises have been recorded has given rise to speculation that religion is likely to be a factor in the events.