Another video today from the NHK Collection, dated December 2, 1941, featuring Mitsubishi Ki-51 "Sonias" from the 27th Sentai and Mitsubishi Ki-21 "Sallys" from the 12th Sentai.
According to the narrator, the "Kitajima butai" (12th Sentai, Col Kitajima Kumao was the unit commander) and the "Sakurai butai" (27 Sentai, Col Sakurai Hajime) attacked Fengchuan (present-day Fengkai County) and Nanxiong on November 28.
It's a rather obscure operation, I couldn't find anything about it in the unit histories. But Monograph #76 mentions:
"With the successful conclusion of the Chungyuan Operation, the Fifth Air Operation (also known as Operation No. 102) was launched at the beginning of August. During this operation the 1st Air Brigade attacked Chungking, Tzeliutsing as well as important areas in north China using Ani airfield while the 3rd Air Brigade attacked ships on the Yangtze River from Kingmen airfield and strategic areas in central China from bases at Hankou and Wuchang...
Although the results obtained during this operation were regarded as satisfactory, on 12 September it was necessary to halt the operation in order to prepare for the Pacific Area Operations."
While the 12 Sentai was under the 1st Air Brigade, the 27 Sentai is not mentioned under any of the two brigades.
A 27 Sentai "Sonia", showing the tail marking of the 1st Chutai, indicated by the slanted white band on the tail.
In this "Sonia" the slanted line is not clearly visible suggesting that it's probably in red. An indication that this particular aircraft belonged to the 2nd Chutai.
A 12 Sentai Ki-21 Model II Koh "Sally" belonging to the 2nd Chutai. Note the complete absence of camouflage and no fuselage hinomaru. The aircraft is finished in overall hairyokushoku.