Due to enormous number of accidents involving bicycles, Japan has imposed a new rule regarding the riding of such vehicle.
From December 1, 2013, cyclists are no longer allowed to cycle on the right of the roads. Meaning, you should be travelling in the same direction as other vehicles (i.e. cars) on your side of the road. Those caught riding in the opposite direction will be sentenced to no more than 3 months jail term, or charged with a fine of no more than 50,000 yen (around SGD615*).
* Based on the horrendous exchange rate of SGD1 = 81.301 yen on December 12, 2013