In the intricate and high-stakes world of Alice in Borderland, the “King of Diamonds” game, also known as the “Beauty Contest” or “Balance Scale,” stands as one of the most thought-provoking and intense challenges in the series. The game, which tests not just intelligence but also logic, probability, and strategy, forces players to confront the fine line between fairness and manipulation. As the players battle to outwit each other in a contest that blends numbers with human psychology, the rules evolve, creating a thrilling atmosphere of tension and uncertainty. But beyond the game’s mechanics, there’s a deeper layer of meaning tied to its name and the character who embodies it—Kuzuryu Keiichi. Let’s delve into the details of the game, its historical and economic roots, and the fascinating backstory of Kuzuryu, the “King of Diamonds.”

King of Diamonds is one of the final “bosses” in Season 2, also known as “Beauty Contest” (manga) or “Balance Scale” / てんびん (Netflix), representing intelligence, logic, numbers, mathematics, and probability.

1. Game Rules

• Players have 3 minutes to choose a number between 0 and 100.
• The average of all the numbers selected by players will be multiplied by 0.8.
• The player whose number is closest to the result will win.
• The 4 losing players will have 1 point deducted, and the round ends. When a player reaches -10 points, they are eliminated from the game. The last player remaining will be the winner.
• Every time a player is eliminated, a new rule is added:
  (+) If 1 player is eliminated: If two or more players choose the same number, they will be eliminated and each player will lose 1 point.
  (+) If 2 players are eliminated: Choosing the exact number will cause other players to lose 2 points instead of 1.
  (+) If 3 players are eliminated: If one player chooses 0, the remaining player can win by choosing 100.

2. Meaning of the Name “Beauty Contest”

The name of the game is based on the famous behavioral economics theory, the “Keynesian beauty contest,” by John Maynard Keynes. In the 19th century, polls were held in newspapers where people voted for the most beautiful woman from a list of candidates. The woman who received the most votes would win the prize.

Economist Keynes compared these beauty contests to stock investment. In the beauty contest, participants did not vote for the person they thought was the most beautiful, but for the person they thought the majority would consider the most beautiful. Similarly, in the stock market, in order to make a profit, an investor should not rely on personal judgment of the intrinsic value, but predict what the majority of the market believes to be valuable.

“Whether it’s chess or poker, any intellectual game requires reading the opponent. But what you read is not psychology, it’s logic.” – Chishiya

3. Kuzuryu Keiichi – King of Diamonds

Before joining Borderlands, Kuzuryu was a successful lawyer who believed that everyone was equal before the law. However, in a lawsuit involving a polluting factory that caused the deaths of twenty innocent people, his client denied responsibility and refused to pay compensation.

At that point, Kuzuryu realized that the law did not exist to protect justice but was a tool to maintain order and power.

This is why Kuzuryu’s “Kuro” game rules are designed to be entirely fair. It is also the reason (in my view) Kuzuryu accepts defeat in the final round. When Chishiya publicly revealed his score, he broke the absolute fairness of Kuzuryu, meaning the game was no longer a competition among equals, and Kuzuryu became the “strong one,” the one who held an advantage in the very world he created, a world he had once considered a symbol of equality.