being used. Freedom of Information Act (FOIA) requests for specific RDF reports remain wanting. "A more critical analysis of the source documentation shows that not one single radio direction finder bearing, much less any locating "fix," was obtained on any Kido Butai unit or command during its transit from Saeki Bay, Kyushu to Hitokappu Bay and thence on to Hawaii. By removing this fallacious lynchpin propping up such claims of Kido Butai radio transmissions, the attendant suspected conspiracy tumbles down like a house of cards." One suggested example of a Kido Butai transmission is the November 30, 1941, COMSUM14 report in which Rochefort mentioned a "tactical" circuit heard calling "marus". (a term often used for commercial vessels or non-combat units). Further, the perspective of U.S. naval intelligence at the time was, "... The significance of the term, 'tactical circuit' is that the vessel itself, that is Akagi, was using its own radio to call up the other vessels directly rather than work them through shore stations via the broadcast method which was the common practice in Japanese communications. The working of the Akagi with the Marus, indicated that she was making arrangements for fuel or some administrative function, since a carrier would rarely address a maru." Japanese radio silence According to a 1942 Japanese after action report, "In order to keep strict radio silence, steps such as taking off fuses in the circuit, and holding and sealing the keys were taken. During the operation, the strict radio silence was perfectly carried out... The Kido Butai used the radio instruments for the first time on the day of the attack since they had been fixed at the base approximately twenty days before and proved they worked well. Paper flaps had been inserted between key points of some transmitters on board to keep the strictest radio silence..." Commander Genda, who helped plan the attack, stated, "We kept absolute radio silence." For two weeks before the attack, the ships of Kido Butai used flag and light signals (semaphore and blinker), which were sufficient since task force members remained in line of sight for the entire transit time. Kazuyoshi Kochi, the communications officer for , dismantled vital transmitter parts and kept them in a box that he used as a pillow to prevent Hiei from making any radio transmissions until the attack commenced. Lieutenant Commander Chuichi Yoshioka, communications officer of the flagship, Akagi, said