Why Wukong accused Tathagata of trickery?

In Journey to the West, when Sun Wukong was imprisoned under the Five Elements Mountain, Guanyin Bodhisattva visited him. Wukong declared, “Tathagata deceived me!” But why did he claim deception? How exactly did Tathagata trick him?

The Prelude to the Wager

Prior to the bet, Tathagata exchanged few words with Wukong. He merely questioned Wukong’s motive for wreaking havoc in Heaven, inquired about his abilities, chastised the monkey for overestimating himself, and finally proposed the fateful wager.

The Terms of the Bet

As stated in the original text:

The Buddha said, “I’ll make a wager with you: If you have the power to somersault out of my right palm, you win. No bloody battles will follow. I’ll ask the Jade Emperor to move to the West and yield the Celestial Palace to you. If you fail, return to the mortal world as a demon and cultivate for ages before causing trouble again.”

— Journey to the West, Chapter 7

As for the scenario where Wukong won the wager, we won’t dwell on it since it never came to pass. Though Wukong knew Tathagata lacked the authority to make the Jade Emperor relocate his court, this wasn’t the crux of the matter. Throughout the gamble, both parties deceived each other to some extent — thus, one cannot place blame entirely on Tathagata. You can refer to this post as to whether Sun Wukong truly escaped Buddha’s palm or not?

The Core Deception

The outcome for losing — “return to the mortal world as a demon” — seemed manageable. Wukong never anticipated being crushed under a mountain. The true deception lay in the disparity between promise and punishment:

• Promised Consequence: Freedom to roam the mortal realm as a demon.
• Actual Punishment: Eternal imprisonment beneath Five Elements Mountain.

A Prison Disguised as a Wager

Wukong ultimately realized the bet was a stratagem to trap him. Tathagata’s goal was never a fair contest — it was to deprive Wukong of freedom indefinitely. Without Guanyin’s intervention (selecting him as Tang Monk’s disciple), Wukong might have remained imprisoned not just 500 years, but for life.