It is generally recognized that the oportunities to use such conventional methods of communication as Flashing Light Signalling, signalling by Hand-flags etc. have decreased in recent years, while more modern means of radio communication have been playing the leading role on board. Turning our eyes to the actual situations in this country, we can find that application of radio telephone is so extensive that there seems no room left for use of Flashing Light Signalling which is taken up as the main subject of this paper. As is well known, the radiotelephone service, called Senpaku Denwa, established by NTT (Nippon Telegram and Telephone Public Corporation) has its service area covering practically all of the coastal Waters of Japan. Various radio communication networks, including those belonging to the VHF radiotelephone in the International Maritime Mobile Service, the Maritime Safety Agency and the fishing industry, are fulfilling their functions effectively, and their further improvements are expected. In such a situation, it will be necessary to reconsider the traditional method of Flashing Light Signalling in Japan. The aim of this paper is 1. to show the results of our analysis on the current practices of F.L.S. in Japan, 2. and to propose some countermeasures which is considered to give the best solution for the existing circumstances.
