In Japan, the regulations regarding carrying a bokken, a wooden training sword, depend on the specific circumstances and location. Generally, carrying a bokken in public areas without a legitimate reason or proper context may be perceived as suspicious or potentially dangerous. It's important to consider the following points:

1. Context: If you are practicing martial arts in a designated training area, such as a dojo or sports facility, it is generally acceptable to transport and carry a bokken as part of your training equipment.
2. Martial Arts Events: When attending martial arts events or demonstrations, it is common to transport and carry bokken for the purpose of participation or exhibition. However, it's advisable to comply with any specific regulations or guidelines set by the event organizers.
3. Transportation: When transporting a bokken, it is recommended to secure it in a bag or case that conceals the sword's shape and prevents any accidental display. This demonstrates responsible handling and helps avoid any misunderstandings.
4. Public Areas: Carrying a bokken openly in public areas, such as streets, parks, or public transportation, without a valid reason may be viewed as alarming or against local laws. It is advisable to avoid such actions to maintain public safety and prevent any unnecessary concerns.

It's essential to be mindful of local laws, customs, and cultural norms when considering the transportation or carrying of martial arts equipment, including bokken, in Japan or any other country. To ensure compliance, it is advisable to consult local authorities or seek guidance from experienced martial arts practitioners familiar with the specific regulations in the area you plan to visit or reside in.