Don't mechanically put Sun Zi's words in reality. Sun Zi has never asked his student to do exactly word for word. He has also said "故其战胜不复，而应形于无穷", it means no victorious act can be repeated exactly, it always have to be adopted to the ground. Otherwise, you know the infamous armchair general Zhao Kuo who not only got himself killed but also 400,000 soldiers with him.
A good example is Marshal Liu Bocheng's 129 division did two ambushes at the same place to the Japanese troops under the same commander. Marshal Liu's act was apparently against the "right" way in the text book. But it is the real right way.
Let's play a mind game. You argue for "one must pretend strong when weak". Since I also read Sun Zi's book, I know that you are pretending strong while being weak, so I call your bluff, what will you do?
Now turn us around. I am weak and I act weak (not following your suggestion), and since you follow the texts of "Sun Zi", will you interpret my "act weak" as "I am actually strong"? You must because you follow the texts, right? So my "act weak" must be the true spirit of Sun Zi's teaching even I act against "his" texts???
The Japanese word for it is Yomi. I am feigning x to deceive you. But then you assume I am feigning x, whereas I am trying to convince you I am feigning x, so perhaps I am feigning feigning x. Using infinite series, we eventually achieve at a convergence, wherein you don't know exactly what I am doing, but I have injected uncertainty into your calculations, with a slight bias towards falling for feigning x.
Take it another way; the Americans during the Cold War understated their weapons systems performance; the Hellfire had a range of about 8km, instead of 4km. On a technological and economic basis, the Americans led the way for much of the Cold War. The Soviets, on the other hand, often overstated their system performance, because they started with a weaker economy and technological base.
The lack of highly-maneuverable J-20 videos is a mystery that implies that absence of evidence is evidence of absence. The actual pros in the CIA and in American military intelligence can very well build a J-20 model, using some assumptions and open-source information, such as the purported 16,000 empty weight, and come to their own conclusions.
