My friend Nick from England post me this answer:
Concerning Blue Oscars . . .
A supplement from Japanese researchers in regard to the Muraoka Hideo interview article mentioned in the magazine "AEROPLANE" which was printed on October 18, 2003.
The article states that the unit's Ki-43 aircraft were never painted blue overall "as some sources have claimed" and speculates that it might be due to weathered dark green paint being misidentified. Because Muraoka refuted the existence of blue Oscars in the unit, 20th Sentai personnel attending a recently held re-union were questioned about it. Several veterans stated that there certainly were some Ki-43s in the unit which were painted dark blue on their upper surfaces.
In October 1944 the 20th Sentai moved under 4th Air Division command with detachments in various locations at Bamban, Caloocan (near Manila), Lingayen (Luzon) and Puerto Princesa (Palawan). On 21 October 16 aircraft moved to Fabrica on Negros Island. They were to provide convoy escort and sea search duties. A 1,500km search area was to be covered from sunrise to sunset, with 2 Ki-43s airborne at any one time, alternated throughout the detachment. This long haul mission of 4 hours was to be flown by aircraft painted blue as special camouflage.
Until recently, these blue painted aircraft were said to be used in Taiwan (Formosa), but in fact only 16 machines which were detached to Fabrica on Negros until December 15th were painted blue. On December 22nd most of the Sentai returned to Hsiaochiang on Formosa and the possibility of the blue painted machines being used there is considered to be low.
The blue paint was called "kon iro" - dark (deep) blue or navy blue. It was not the bright cobalt blue seen in so many profiles but actually a rather dark, purplish blue as recalled by the veterans.
About the blue Sonia I have no specific knowledge.
Hope this helps.
Best regards
Nick
