The main contents of this issue are: The Trump administration declassified the "Indo-Pacific Strategy" document 30 years in advance, exposing the essence of the "hegemonic strategy"; Sino-US cooperation is mutually beneficial, and fighting will hurt both; Sino-US relations will spiral downward in 2020 and fall to the low point since the establishment of diplomatic relations; the "four-party mechanism" and "five-eyed alliance" will be vigorously engaged in, and the US "group anti-China" will be unpopular. ("New Observation on Defense" 20210219 Spring Festival Special Program "Indo-Pacific Quadrilateral" and "Five Eyes Alliance" in the Year of Change)