#Zone Conversion Procedure — Translating Castles into co Zones

Contents

Scene Tool. The spine of this volume — every structure and mode document in 02~07 references these 4 steps as its compliance base. Castles need no new numbers. A castle gate is already a narrow path, the top of a castle wall is already high ground, and the honmaru is already the Core Zone. This document is a dictionary for translating castles into existing co tools, not a new rule set (fc cannot overwrite co Canon).

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#Scent — Same Stone, Four Names

One person stands before the same castle gate four times.

To the attacker, that gate is a wall to break. To the defender, it is the last locked line. To the infiltrator, it is a shadow to sidestep, and to the explorer walking through ruins, it is a collapsed tomb.

Same stone, four names. A structure is not a fixed number, but a scene function that turns on by viewing angle — so one castle can be used four times. This document teaches that translation.

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#Law 0 — Grand Principle of Conversion

Do not create a separate stat system for castles. All numbers come directly from co canon.

• Fortress Defense = co-03-10: palisade 12 / stone castle 15 / great castle 18. This value is the Defense of castle gate and wall zones on the battlefield.
• Breakthrough and Blockade Target Numbers = co-05-03: normal Breakthrough 11 (advantage)/13 (complete control), Blockade Breakthrough 15. (2d10 + Courage ≥ Target Number, cost 3 Energy.)
• Checks, time, durability = co conventions as written: 2d10 + attribute + skill ≥ Target Number, time = round, durability = Wounds (no HP), ranged shooting = Archery (no separate gun skill).

Do not create new gimmicks, new skills, or new dice. The only judgment the GM makes in this volume is "which co gimmick should I attach?"

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#Law 1 — Step 1: Check Scene Function

Ask seven questions in front of the structure. Turn on only 1~2 functions for one structure (no overloading).

1. Does it block? (cuts Approach and forces detours)
2. Does it hide? (gives sightline concealment and stealth)
3. Does it give height? (advantage in shooting and sightline)
4. Does it cut sightlines? (melee chaos and Surprise Attack)
5. Does it gather troops? (mustering and waiting)
6. Does it protect supplies? (water, food, gunpowder)
7. Does it connect to the Core Zone? (to the final objective)

The same structure turns on different functions by mode — a castle gate is "does it block?" in siege, and "does it hide?" in Infiltration. The role in today's scene comes before historical accuracy.

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#Law 2 — Step 2: Assign Zone Property (Function → co Gimmick Dictionary)

Translate Step 1 functions into gimmicks from the co-05-05 gimmick catalog. Quote the gimmicks as written; do not invent new ones.

The main gimmicks for human siege are narrow path + wall + high ground + fire. Barrier and Spiritual Taint are turned on for castles involving yoma (Infiltration and ruin modes).

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#Law 3 — Step 3: Assign Scene Pressure (Mode Switch)

Layer scene pressure onto the same zone. Pressure is not a new number, but repackaging of existing rules — and which pressure turns on is what determines the mode.

The pressure bundle determines the mode:

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#Law 4 — Step 4: Compress into a Battlemap

Do not draw one castle as one map. Keep only the 3~7 zones important to today's scene, and mix structures with different purposes (castle gate, watchtower, inner yard, well, storehouse, secret passage), preserving the co-05-01 identity of "3~7 zones for one combat."

Do not draw new example maps; quote co-05-06 30 battlemaps as written:

• siege pressure battle → 03 castle gate pressure battle ([castle gate passage (Front Zone, narrow path cap 4, barricade)])
• defense counterattack → 21 fortress counterattack (inside-castle side has high-ground advantage, outside-castle side has reinforcement Rear Zone)
• collapsed wall → 13 gap in the collapsed wall ([Core Zone: wall gap, standard melee chaos])
• mountain temple/Barrier defense → 19 mountain temple defense ([Core Zone: inside the dharma hall (objective point, Barrier)], bell tower (high ground))

The "fortress assault recipe" in [co-05-05] ([outside castle]──[castle gate (narrow path, cap 3)]⇌[inner yard (barricade)]↕[wall top (high ground)]↕[main castle (Core Zone: lord-tier residence)]) is the complete form of the conversion. No wargamification — keep small zone combat.

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#Format — Structure Conversion Card (5 Fields)

Every card in structures fills these 5 fields. Here, only the blank format and standard are given — actual data (otemon, moat, watchtower...) is filled by 02-02.

Structure Name (Kanji)
├ Scene Function : (1~2 of the 7 questions in Law 1)
├ Zone Property : (co gimmick from the Law 2 dictionary — link)
├ Scene Pressure : (the mode-specific items turned on among the 6 pressures in Law 3)
└ GM Hook    : siege / defense / Infiltration / ruins — one line each

The GM Hook 4-mode slot guarantees this volume's reuse economy at card level — one structure has a different line in each of four modes.

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#Operation Dial — 5-Minute Session Prep

1. Set the stage. Which kuruwa, gate, or watchtower is today's place?
2. Pick 3~7 zones. Mix structures with different purposes (Law 4).
3. Attach gimmicks. Give each zone 1~2 co gimmicks from the Law 2 dictionary.
4. Turn on pressure. Call mode-appropriate pressure (Law 3) as clock, Popular Support, or Barrier.
5. Open an example. Vary the nearest map among the [co-05-06] 30 examples.

Lookup tables (which structure maps to which gimmick) are in the quick reference. This document only gives the procedure flow.

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#Scent — One Sentence

"A castle does not ask for new rules — it only asks from which angle to read the rules already present."