#Infiltration Guide — Reading the Promise Backward

Contents

Scene Tool. This is the mode for entering a castle without opening it. If siege asks "how do we open it" and defense asks "how many days can we hold," Infiltration asks "what do we steal or rescue without opening the gate?" Every ruling follows 02-01 and 02-02, and does not create a new Infiltration check system — existing non-combat checks and Outside Zone rules are enough.

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#Scent — One Who Reads the Promise Backward

The castle gate is a promise made to keep someone inside — read that promise backward, and the way in appears.

In the corner of an inn, two water carriers speak. "The otemon guard post changes at the hour of the dog." At dawn the next day, there is one more water carrier. In his yoke passing the rear gate by the well, he carries not water, but — darkness. A castle's daily routine is its weak point.

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#Mode Overview — Without Opening the Gate

Central question: what will be stolen or rescued without opening the gate?

The Infiltration side is trying to obtain the target, rescue a hostage, steal information, or confirm a seal, then exit undiscovered. The defending side is trying for discovery, blocking, and capture.

Infiltration has only two endings:

1. Undiscovered success — slip out without anyone knowing entry happened.
2. Discovery — this mode has no way to fail quietly. The instant discovery happens, it immediately shifts to a siege or defense scene (hold out from inside, or force matters from outside).

Infiltration is a small-scale (1~3 person) scene — do not bring a squad inside. Heavy footsteps wake the promise.

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#Scene Bundle — Five Scenes

Each scene = one small map, or one knot of non-combat checks.

#① Rumor Gathering (Castle Town)

Dig up guard-shift times, guard numbers, possible collaborators, and well/kitchen/sewer locations. Main checks = Negotiation, bribery, Deceit, Scouting. Results accumulate as "fact cards" — each thing learned becomes one modifier in a later scene (castle town is a social zone).

#② Securing a Disguised Identity

Obtain an identity that blends into the castle's routine, such as water carrier, peddler, mendicant monk, or laborer. Main checks = Disguise (identity disguise) and Deceit (enduring questioning). A disguise is a timed tool that works only until the first opposed Perception check.

#③ Internal Route Infiltration

Avoid the main gate and enter through kitchens, warehouses, wells, shrines, sewers, cliffs — gaps in the promise — then move to a zone adjacent to the Core Zone. Main checks = Infiltration (opposed), Lightness Skill (cliffs/roofs), Disable (locks/bars). The Outside Zone is the infiltrator's corridor (§Zone/Check Connections).

#④ Guard Shift and Routes

Use patrol routes and blind spots in guard-shift timing to manage discovery pressure. Tool = discovery pressure track (§Zone/Check Connections — a reduced borrowing of the 04-02 clock for Infiltration). Shift timing turns on Infiltration +modifier / Perception -modifier.

#⑤ Core Zone Arrival

Reach the innermost area holding the target (secret text, hostage, seal stone), perform the target action (theft, rescue, confirmation), and get out. The Core Zone is translated as Core Zone "boss lair" or "objective point." Exit failure = shift to siege or defense.

Do not resolve all 5 scenes in one session. Today ①②, next ③④, then ⑤ — each scene is one independent map.

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#Zone and Check Connections — Translation into co Rules

Follow the 02-01 conversion procedure. Every Infiltration rule is a rearrangement of co Outside Zone, Core Zone, non-combat, and skill-list rules. The only device this mode adds is one discovery pressure track, and even that is a GM operating clock, not a numerical system.

#Outside Zone = Infiltrator's Corridor

Underground passages, roofs, cliffs, sewers, and deep forest are Outside Zone zones. Quote the entry conditions as written (do not create new entry methods):

Path for a non-shinobi party: enter Outside Zone with Infiltration Master or Lightness Skill Licensed/Master, or open a gap with cliff Lightness Skill ≥ 13 (rope +2, co-03-09), sewers, or Disable locks. The Outside Zone has no Domination concept.

#Core Zone = Where the Target Is

The innermost area is Core Zone "boss lair (type 3)" or "objective point (type 2)." The ideal of Infiltration is to arrive and leave without fighting, so Core Zone combat rules (Domination offset, mistaken shooting, forced Breakthrough fixed 13) operate only if discovery turns it into combat. An undiscovered Core Zone is only "a room where the guard's back is turned."

#Non-Combat Checks (All co Citations)

Environmental modifiers (co as written — no new modifiers):

• night Infiltration +3, but all checks -2 (exception adjacent to lights) (co-03-09).
• fog Infiltration +3, ranged -3.
• forest/brush Infiltration +2, narrow interior Infiltration +2 (co-05-05).
• Defender Perception: guards and patrols with Perception Licensed/Master make opposed Infiltration harder (surprise is outer perimeter entry +2, and Outside Zone entry is enhanced surprise — co-03-06).

If ranged action is needed, it is Archery (covering bows and teppo) — there is no separate gun skill.

#Discovery Pressure Track (Infiltration-Version Clock)

A tick device for tracking guard routes and shifts. It borrows a reduced form of the 04-02 holdout clock for Infiltration (the clock is defined by 04-02 — this document does not redefine it). It is a short alert track (3~4 boxes), and the tick unit is the scene (not round or turn).

When the track fills, alert stage rises (more patrols, Perception +modifier) → final box means discovery → siege or defense shift. Track advancement does not roll dice — it is a GM operating device.

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#Table Hooks — For the GM

Theme. "A castle's daily routine is its weak point." And — "whose side is the collaborator on?"

Scenario Hooks:

• Hostage rescue — extract someone imprisoned in the sannomaru jail. If discovered, the hostage is endangered first.
• Powder store reconnaissance — confirm only the location, then leave. This information becomes the fire attack scene in the next 03 siege.
• Seal confirmation — is the seal below the shrine intact? If broken, this castle will soon become 06 ruins (foreshadowing).
• Collaborator rendezvous — meet the ally inside. But is he truly on your side? (betrayal = discovery pressure spikes).
• Forged pass — the road that walks proudly through the main gate. Everything hangs on one opposed Disguise/Deceit check.

Mode Shift on Failure — Keep Using the Same Kageyama Castle:

Infiltration is "win quietly, or loudly become another mode." The smoother that transition is, the more Kageyama Castle lives four times as one stage.

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"The castle gate is a promise that locks someone in — the infiltrator reads that promise backward while the one who locked it sleeps."