The concept of special circumstances of risk of collision has been frequently used in Japan marine accident inquiry. This is a term used when danger of collision was judged to arise from an innocuous passing due to the action of a ship. No equivalent of this can be found in overseas marine accident inquiry, so it is presumed that the term is a Japanese-specific circumstance in which various sized ships are congested in a narrow sea area. Although this concept has been pointed out and examined before, it is not revealed how it is used.
This paper considers the consistency of judgements of Japan marine accident inquiry and Act on Preventing Collisions at Sea. The investigation of the application of special circumstances of risk of collision in Japan marine accident inquiry was carried out, and the use of this term was examined. The results showed.