had knocked out many of the ships' anti-aircraft defences. Aircraft attacking from several directions at once had confused and overwhelmed the Japanese defences, resulting in lower casualties and more accurate bombing. The results therefore vindicated not just the tactics of mast height attack but of mounting coordinated attacks from several directions. The Japanese estimated that at least 29 bombs had hit a ship during the battle. This was a big improvement over the Battle of Wau back in January, when Allied aircraft attacked a Japanese convoy consisting of five destroyers and five troop transports travelling from Rabaul to Lae, but managed to sink just one transport and beach another. Imamura's chief of staff flew to Imperial General Headquarters to report on the disaster. It was decided that there would be no more attempts to land troops at Lae. The losses incurred in the Bismarck Sea caused grave concern for the security of Lae and Rabaul and resulted in a change of strategy. On 25 March a joint Army-Navy Central Agreement on South West Area Operations gave operations in New Guinea priority over those in the Solomon Islands campaign. The XVIII Army was allocated additional shipping, ordnance and anti-aircraft units, which were sent to Wewak or Hansa Bay. Of the defeat, Rabaul staff officer Masatake Okumiya said, "Our losses for this single battle were fantastic. Not during the entire savage fighting at Guadalcanal did we suffer a single comparable blow. We knew we could no longer run cargo ships or even fast destroyer transports to any front on the north coast of New Guinea, east of Wewak". The planned movement of the 20th Division to Madang was revised in the light of events in the Bismarck Sea. The operation was postponed for two days, and the destination was altered from Madang to Hansa Bay further west. To reduce the Allied air threat, the Allied airfield at Wau was bombed on 9 March and that at Dobodura on 11 March. Three Allied aircraft were destroyed on the ground and one P-40 was lost in the air but Allied fighters claimed nine Japanese aircraft. The transports reached Hansa Bay unscathed on 12 March and the troops made their way down to Madang on foot or in barges. The 20th Division then became involved in an attempt to construct a road from Madang to Lae through the Ramu and Markham Valleys. It toiled on