Japan is perhaps the safest industrialized country in the world. The crime rate, especially violent crime rate, is incredibly low. Theft is incredibly uncommon as well. The sense of goodwill is so great that I’ve known strangers to chase you down if you drop your wallet and convenience store cashiers to run out of the store to give you seven yen you forgot at the counter.
When it rains, however, all bets are off on bicycles and umbrellas. Thefts of these two items are extremely common. The part that perplexes many foreigners is the Japanese individual does not view it as theft. Once the rain is over or they have reached their destination they don’t keep the umbrella. One assumes they view it as borrowing, though don’t expect them to return the item to its owner or where they found it.
The same is true of bicycles, whose disappearances are not exclusive to the rain. As soon as they are ridden to the destination (usually the train station) they are abandoned. Consequently, many train stations have a section that while once may have been a bicycle parking lot is no more of a bicycle graveyard. There are few sites like one hundred plus abandoned bicycles crowded together.
A fair warning though: Many foreigners in the past have used this grave yard to get a free bicycle. I’d advise against this. While the bicycle may have been abandoned, it probably wasn’t by its owner. Knowing that some foreigners take the abandoned bicycles, it is incredibly normal to be stopped by a police officer and for them to ask about your bicycle and its registration. It happened to me about once a month, my coworkers more, and we all bought our bicycles first hand. You don’t want the police to find the bicycle you’re riding is registered to someone else and listed as stolen. And yes, they register bicycles in parts of Japan.