Biking in Tokyo is more casual and for short distance, people don't bike to work, they bike to the nearest train station or shopping street. It is very different attitude, there is no need for helmets, the speed is low and there are no dedicated lanes, most traffic is mixed with pedestrian traffic. I find it much nicer than the lycra culture of biking in countries like the US or Australia, but each biking culture makes sense when considering the different environments.