17.【Rekiden】Let AI vs AI Drive History Automatically

Give It an Evaluation Function, and Sengoku Moves on Its Own

tags: [AI, ChatGPT, Game Design, Automation, Sengoku, Simulation]

🏁 Introduction

In Rekiden-15, we showed that
“just pasting a template into AI is enough to start a game.”

In Rekiden-16, we clarified that
AI behaves as an FSM (Finite State Machine).

Now comes the next question.

Can history progress without a player?

The answer is YES.

🎯 Conclusion: Give AI an Evaluation Function, and It Will Fight on Its Own

The final key that turns AI into a game system is the:

Evaluation Function

• What is considered “good”
• What is considered “bad”

Once this is defined,
AI will keep choosing actions even without human input.

🤖 What “AI vs AI” Means in Rekiden

In Rekiden, AI vs AI is defined as follows:

• Takeda AI: acts according to Takeda’s evaluation function
• Uesugi AI: acts according to Uesugi’s evaluation function
• Progression AI: manages state and transitions only

👉 The key idea is role separation.

🧮 Minimal Evaluation Functions

Takeda Clan AI (Example)

Evaluation Criteria:
- Preserve own troop strength
- Expand control over Shinano
- Ensure survival of key commanders
- Avoid reckless frontal assaults

Uesugi Clan AI (Example)

Evaluation Criteria:
- Superiority in direct confrontation
- Maintain morale
- Secure battlefield initiative
- Minimize withdrawals

This is already sufficient.

🔍 Why This Works

At each turn, the AI implicitly performs:

1. Understand the current state
2. Enumerate possible actions
3. Score each action using the evaluation function
4. Select the action that seems “best”

This is a textbook example of:

Decision-Making AI

🔁 Example of AI vs AI Progression

Turn 1:
Takeda AI: Prepares the Woodpecker Strategy (force preservation)
Uesugi AI: Fortifies positions and prepares to intercept
→ State: Sustained tension

Turn 2:
Takeda AI: Advances a detached force
Uesugi AI: Detects movement and shifts main forces
→ State: Local engagement begins

Turn 3:
Both AIs: Evaluation drops due to rising attrition
→ State: Full-scale battle

No human input is involved.

📜 This Is “Automatic War Chronicle Generation”

At this stage, Rekiden is no longer:

• A game ❌
• A novel ❌
• A historical explanation ❌

👉 It becomes an automatic war chronicle generation system.

With the same template:

• Change the evaluation function
• Change personality (cautious / aggressive)

and you get a different history every time.

⚖️ Plausibility Over Reproducibility

What matters is not:

“Did it match historical fact?”

but rather:

• Does it feel plausible?
• Does it make sense for a Sengoku warlord?

Rekiden deliberately entrusts this judgment to
AI’s commonsense reasoning.

🧭 The Endpoint of Rekiden

Across Rekiden-15 to 17, the system evolves as follows:

• 15_: Template = initial state
• 16_: AI = FSM
• 17_: AI = decision-making agent

This results in:

A historical simulation that requires no game engine

⚠️ What Makes This Dangerous (Important)

To be honest:

• It can generate infinite alternate histories
• It can progress beyond human intent
• It can mass-produce “plausible lies”

This power is both strong and dangerous.

Rekiden is also:

An experiment to observe that boundary

🧪 Possible Directions Beyond 17_

• Numerical evaluation functions
• Alliances and betrayals between multiple AIs
• Year-by-year autonomous historical progression
• Educational and research-oriented simulators

Beyond this point,
we are firmly in research territory.

✍️ Closing

AI is no longer merely
“something that answers questions.”

It is an entity that holds state, evaluates, and acts.

Rekiden-17 marks the moment when:

AI is promoted to a “subject of history” itself

(To be continued)