Understanding is business; not understanding is a joke: Why in Japan should you never trust the other person's politeness?

I recently discovered a very interesting phenomenon: many people go to Japan to do business or interact, and after returning, they feel like they've caught a disease—not physically tired, but mentally exhausted.
I used to take this wrong turn myself. I remember once negotiating a partnership with an organization in Tokyo, and throughout the process, they kept smiling, nodding wildly, and constantly saying "Hai," which was very inspiring—thank you for your effort.
When I walked out of the office building and looked at the streets of Shinjuku, I thought I was a business genius; this deal was absolutely rock solid.
But then, I waited back home for a whole month, and they didn’t even give a polite reply.
Later, I realized that those nods and saying "okay" only meant they were listening, not that they agreed.
This is a typical cognitive bias. We are used to being straightforward, thinking in black and white, but in Japan, there is an inherent ambiguity.
They strongly oppose aggressive sales tactics and pushy approaches.
There, any valuable negotiation must be like water—gentle and steady.
If you expect to win by using aggressive logic and momentum like in other places, you are destined to lose.
This personality trait is even embedded in their historical turning points.
Look at World War II: the US and Russia spent so much effort, and when it came to that point, how did Emperor Hirohito explain surrender to his people?
In that famous broadcast, he refused to say "we lost" or "we surrendered."
His wording was: "The development of the military situation may not be favorable to Japan."
Think about this phrase carefully.
Even when the country was almost reduced to ruins, he still used this ambiguous, extremely vague way to leave a veil of shame.
Japanese culture does not promote directness; no one will directly refuse you, no one will outright say no, but they also may not say yes.
Later, I realized a key point: in complex negotiations, language is often the cheapest surface, while the emotions and rhythm in the air are the true underlying code.
The logic here is a kind of quantum superposition.
You simply cannot guess the other person's thoughts based on literal meaning.
Once you start understanding this art of leaving space, you can not only understand Japan but also see through most of the complex利益局 (interest games) in this world.