Here is the latest update from the Tokyo Marathon website:

To Runners Planning to Wear Costumes

We understand that wearing of costumes and putting on a disguise is one of the enjoyments to participate in a major marathon event. On the other hand, it might cause the runner itself to fall, and also make the other runners or audience feel uncomfortable.

Please be advised that in order to permit wearing of costumes in the future, we request for each runner to understand the circumstances and extend exercise of their sensibility.

The organizer will prohibit all costumes stated from 1 to 6 below and other related behavior that may disrupt public order and other standards of decency. In the event that the organizer finds behavior related to this notice the runner will be immediately disqualified from the race. We will not accept any objection upon our decision in relation to this matter.

1. Clothing that may harm others, induce fall, and conduct that may interfere with others.

Example 1: carrying a knife or a sword, wearing armor or costumes with rivets etc.
Example 2: long skirt, kimono etc.
Example 3: holding of hands among the runners

2. Clothing not appropriate for a sporting event that may cause discomfort to others.

Example 1: running naked, wearing of costumes or underwear that may resemble nudity.

3. Wearing of clothing intended to promote political preferences or views, religious belief and advertising of products or establishments other than the event sponsors.

Example 1: sash containing political party or candidate names, religious beliefs.
Example 2: costumes resembling a political or religious figure or merchandise other than the event sponsors.

4. Usage of fireworks, whistle and lighting apparatus etc. that may be used to distract or misguide other runners.

5. Wearing of clothing requesting of a donation or signatures for a petition etc.

6. Other clothing or costumes deemed inappropriate by the event organizer.

Tags: marathon, marathons, Tokyo Marathon, running