'Pastel II' was the US unrealised deception plan developed from 'Pastel I' and designed to conceal the real nature of 'Olympic' by means of attacks against Japanese targets on Formosa and feint landings at Shanghai in China and on Shikoku island in the Japanese home islands (August 1945).
In July 1945 there was a conference in Manila between Admiral the Lord Louis Mountbatten and General Douglas MacArthur, heading the South-East Asia Command and US Army Force Pacific command respectively. After this conference’s recommendations for revised strategic movements, there was a major revision of the Allied deception plans, and of these the only scheme to receive detailed development was 'Pastel' (now 'Pastel I'), which was developed into 'Pastel II'.
Preliminary work had started on 'Pastel I' even before it was approved, initially with the outline development of communications deception requirement on 23 June, and on 4 July there emerged the idea that the attention of the Japanese might be drawn to the Shanghai area in August if the Chinese government could be induced to make a diplomatic inquiry of the governments with concession rights in the Shanghai International Settlement with regard to the future status of those rights; this got nowhere. After meetings of the communications officers from the theatre and fleet staffs plus a representative of the Joint Security Control, a member of the deception team was able on 31 July to advise on X-90 (about August 1 under current planning for 'Olympic') and continuing to X-50 though possibly extended to a later date, the radio deception plan linking various headquarters in China and various commands in the Pacific would begin, and suggest preparations for an amphibious descent on the Chusan and Shanghai area on X-31.
Late in July there emerged a way to draw Japanese attention to Shanghai, where the Chinese underground movement was under US control. Captain Milton E. Miles, commander of the US Naval Group in China, suggested that on about 1 August his group should start to train 1,500 key personnel in Shanghai for intelligence gathering, sabotage of Japanese installations, and protection of the port against Japanese sabotage. The Joint Security Control advised a member of the deception team that pirate activity in the East China Sea, presumably also controlled by Miles, could also help the effort.
Over this period detailed planning had continued in Manila, and on 30 July MacArthur’s director of operations issued a staff study for the definitive 'Pastel', which now received the designation 'Pastel II' to differentiate it from the original plan, which now became 'Pastel I'. According to 'Pastel II', 1 December rather than a date late in December was now the notional target date for an amphibious assault on Shikoku, and this also reflected a new consensus among the deception planners about the size of the total force to be suggested for the assaults on Chusan and Shikoku. Other changes effected in 'Pastel II' were the use of tactical airborne diversions (drops of dummy paratroopers) during the night before the actual landings, in the form of drops of dummy paratroops, 'Pintail' landers designed to fire Verey signal flares, and 'Bunsen Burner' loudspeakers attached to parachute-landed radio receivers, and to provide greater verisimilitude to such devices, the arrival in Okinawa of a notional airborne corps from about 20 August. Detailed responsibilities, including special means and related activities, were laid out. This staff study was followed on 5 August by a formal operational instruction detailing the timing of each action and the responsibilities for its implementation.
In Washington, DC, a draft staff study outlined a naval tactical deception plan, including a feint towards Shikoku from X-15 by forces heavily protected against kamikaze attack, with appropriate 'Beach Jumper' visual deception and similar activities, culminating in a feint landing on X-5, and another feint against the north-western part of Kyushu, well away from the actual 'Olympic' landing points, from X-7 to X+15.
On 31 July a member of the deception planning team asked the Joint Security Control for unit designations for a notional airborne corps and airborne division for 'Pastel II', as well as 1,000 shoulder patches for the latter. The designations allocated to the two notional formations were the XXXV Airborne Corps and the 18th Airborne Division, while the real 11th Airborne Division, in the Philippine islands group, was notionally the other division in the corps. To promote the idea of airborne action, on 8 August the Joint Security Control was requested to supply factual or special means implementation of a statement by Major General Matthew B. Ridgway, the celebrated commander of the XVIII Airborne Corps in the European theatre, to the effect that he would soon be transferred to the Pacific theatre, and it was recommended that this could be made to seem less like a planted story if it took the form of a press release by the Department of War, but the war ended before anything could be done.
A proposed master schedule was created for special means from August through the end of the year, these including the items already requested.
A persistent and significant theme was the delay or postponement of forthcoming operations as a result of factors such as the logistical problems associated with the redeployment of US forces from Europe, and a report that General George C. Marshall, the US Army chief-of-staff, had told President Harry S Truman that Japan could not be invaded until most of that nation’s military and industrial objectives had been destroyed and a full air and sea blockade had been effected. A general theme, like the similar 'Bodyguard' in the European theatre, was that the successful implementation of the bombing offensive might render any invasion unnecessary.
The focus on China continued with items such as a report that the Coast and Geodetic Survey had completed a study of the Chinese coast, a report that volunteers were being sought to go to China to help train Chinese troops, reports of a new US-equipped Chinese 6th Army, and a report that a group of Chinese-speaking censorship officers was being assembled in California. There were also reports that Lieutenant General George C. Patton was being considered for an army command in China.
The threat in the north was supported by such items as a report that two infantry divisions stationed in the southern USA had been issued with arctic clothing. Not much more than that was ever done about the northern threat, though on 5 July there began preliminary investigations about radio links between Major General Curtis E. LeMay’s 20th AAF in the Mariana islands group and the Aleutian islands group. Work continued on communication links between the Aleutians and the other theatres, and the Operations Division of the Department of War’s general staff developed the concept of moving to the Aleutian islands group real airborne units returned from Europe, but representatives of the Alaskan Department never attended communications planning conferences, and nothing comparable with 'Wedlock' was ever constituted in the north. It was always borne in mind by the US deception planners that too great an emphasis on the north might detract from the supposed threat of an invasion of China. Moreover, some US navy and USAAF elements still hoped that there might really be such an operation, to be named 'Keelblocks'.
On 7 August it was ordered that a start was to be made on 'Pastel II' communications deception on 10 August, but on 16 August 'Pastel II' was cancelled in light of Japan’s surrender.