Because these two traffic systems are crossing in the Kii Suido (Strait), this means that this is an area in which it is necessary to be on the alert at all times. Article 15 of COLREGs (Crossing Situation) was most generally applied in this area.However, as can be seen on the map, the crossing of vessels in this area takes place at an angle close to overtaking, and if thegive-way vessel uses a change of course in order to avoid collision, she is forced to use a large angle to change course.In the case explained in this report, if Vessel A used a momentary heading manoeuvre in the direction of the astern ofVessel B in order to avoid collision, she would have to change course from 190 to 248 degrees