#Josai Kobo-ki Overview

Contents

This document does not carry detailed cards for castle structures or scenario text. It is an entrance for quickly choosing which rules to read a castle through, and whether to unfold it as siege, defense, Infiltration, or ruin exploration.

#1. What This Volume Does

fc12 covers the following.

General background knowledge on Japanese castles of the Sengoku period.
Procedure for converting castle structures into Konsei Reiyotan zone/battlemap rules.
Siege scene guide.
Castle defense and holdout scene guide.
Infiltration scene guide for castle settings.
Abandoned castle/ruin exploration scene guide.
Sample scenario using one fictional castle from four viewpoints.

fc12 does not replace the following.

It does not replace co zone, squad, domain, or combat rules.
It does not fully catalog every Sengoku-period castle like a historical encyclopedia.
It does not process all large-scale war as a separate wargame.
It does not attach an independent stat system to every castle structure.

#2. Castle Structure Conversion Principles

Convert castle structures in the following order.

Check Scene Function

Does it block?
Does it hide?
Does it give height?
Does it cut line of sight?
Does it gather troops?
Does it protect supplies?
Does it lead to the Core Zone?

Assign Zone Properties

Narrow path.
High ground.
Wall/barricade.
Blockade.
Breakthrough objective.
Core Zone entrance.
Domination modifier.

Assign Scene Pressure

Time pressure.
Supply pressure.
Morale pressure.
Popular Support pressure.
Yoma/Spirit Realm pressure.
Internal betrayal or collusion.

Compress into a Battlemap

Do not draw an entire castle at once.
Keep only the 3~7 zones important to today's scene.
Mix zones with different purposes, such as the castle gate, watchtower, inner yard, well, storehouse, and secret passage.

#3. Major Structure Candidates

Structure	Scene Function	Zone-Ruling Candidates
otemon / castle gate	Breakthrough objective, center of pressure battle	wall, Blockade, Breakthrough, high Defense
moat	blocks Approach, forces detour	narrow path, dangerous terrain, movement cost
earthwork / stonework	defense line, fall danger	high ground, wall, collapse danger
watchtower	sightline, shooting, signal	high ground, Domination modifier
honmaru	final Core Zone	Core Zone, command zone
ninomaru / sannomaru	middle defense line	multiple zones, retreat line
well	holdout resource	supply objective, poisoning/contamination hook
storehouse	food, gunpowder, loot	supply, fire attack, explosion danger
shrine / small shrine	Barrier, oath, taboo	Core Zone, Barrier, yoma hook
castle town	Popular Support, rumors, Infiltration route	social zone, information zone
secret passage	Infiltration, escape, betrayal	hidden connection, Infiltration objective

#4. Four Use Modes

#Siege

The attacking side pressures the castle from outside to inside.

Scouting and securing Approach routes.
Choosing the castle gate or a weak wall.
Fire attack, ladders, Bribery, collusion.
Squad losses and morale management.
Pressuring the honmaru after the final Breakthrough.

#Defense / Holdout

The defending side closes the castle and endures.

Supplies and well status.
Castle gate reinforcement.
Popular Support and refugees.
Wounded and squad fatigue.
Finding collaborators.
Clock until escape or relief force arrival.

#Infiltration

A small group enters while avoiding the castle's rules.

Gathering castle-town rumors.
Disguised identity.
Kitchen, storehouse, well, shrine, sewer, cliff.
Guard routes and shift times.
On failure, immediately switch to a siege/defense scene.

#Ruin Exploration

Explore the castle left after war.

Collapsed castle gate and blocked passages.
Remaining arms and masterworks.
Bound spirits, yoma, seals.
Traces of past battles.
Survivors or descendants inside the ruins.

#5. Sample Castle

The sample stage is Kageyama Castle (影山城).

The basic setup is as follows.

Item	Value
Form	mountain castle
Location	border zone where two roads and one mountain path meet
Core Resources	mountain well, gunpowder storehouse, small shrine
Defensive Features	narrow uphill path, double castle gate, high watchtower
Weaknesses	old secret passage, tension with the castle town, dry well
Spirit Realm Element	shadow gate sealed beneath the shrine
Current State	changes by scenario mode into active castle, besieged castle, Infiltration target, or ruin

The four uses are divided as follows.

Mode	Central Question
Siege	How will Kageyama Castle be opened?
Defense	How many more days can Kageyama Castle hold?
Infiltration	What will be stolen or rescued without opening the castle gate?
Ruin Exploration	What remains after Kageyama Castle has fallen?

#6. Reading Order

A first-time GM can read in this order.

Use 01-01 and 01-02 to establish the castle structure and Approach routes.
Use 02-01 and 02-02 to connect structures to zone/battlemap rules.
Choose whether today's scene is siege, defense, Infiltration, or ruins, then open one of 03~06.
If an immediately usable stage is needed, use 07-01 Kageyama Castle and 07-02 4-mode use.
During a session, check only structures and modes in 99-01 quick reference.

#Scent — One Sentence

"The same castle is a gate to the attacker, a wall to the defender, a shadow to the infiltrator, and a tomb to the explorer."