#Spirit Realm Tides — The Barrier That Rises Four Times a Day

Contents

Core reference: Zone Gimmick Catalog (區域仕掛圖鑑)

The incense sways quietly. The angle of the smoke changes. The tide comes in. The Spirit Realm has no sea, but something unseen rises and recedes. This file calls that something the "tide."

#1. What the Tide Is

The Spirit Realm tide is a periodic shift in the pressure applied to the barrier dome. At high tide, the currents outside the dome press inward; at low tide, they withdraw. PCs sense this shift through the angle of incense smoke, the cloudiness of the dome surface, and the weight of the air.

The source of the tide is unknown. Several accounts circulate: that it is the influence of a central celestial body, that it is the breathing of the hells, or that it is the barrier's own inherent rhythm. In practice, the GM may choose any of these. If PCs ask during a session, the answer closest to the mood is "no one knows."

#2. Four Cycles in a Day

#Basic Cycle

A day is not measured in 24 hours, but in "six koku(刻)." One koku corresponds to 4 hours of real time. The tide changes once every two koku, forming four cycles in a day.

The 1st high tide(first high tide) arrives in the deepest darkness just before dawn. The 2nd high tide(second high tide) arrives in the twilight just before sunset. Low tide occurs near noon and midnight, and deep low tide in particular is the time slot when barrier pressure is lowest.

#The Feel of the Cycle

Even if the PCs do not have a clock, they can estimate the tide through the following three sensations.

1. Direction of incense smoke: at high tide it is drawn inward, and at low tide it spreads outward.
2. Transparency of the barrier dome: at high tide it is cloudy, and at low tide it is clear.
3. Distance of sound: at high tide all sounds feel close, and at low tide they feel distant.

At each time-slot transition, the GM describes one of these sensations. The passage of session time is naturally marked through this description.

#3. Rule Effects of the Tide

#High Tide Effects

Effects applied during first high tide or second high tide time slots.

Incense burning faster means that the lifespan of the incense the PCs carry is shortened. If the scenario deliberately places incense-consuming scenes at high tide, resource-management pressure increases.

#Low Tide Effects

Mid tide and deep low tide time slots.

Low tide is a relatively favorable time to stay in the Spirit Realm. However, the severe drop in barrier pressure at deep low tide creates a separate danger: incidents in which yoma slip into the domain through weak points in the barrier. Many events in 03-05 Boundary Events happen more often at deep low tide.

#Tide Transition

The transition between koku has a passage interval of about 10~15 minutes(real time). During this interval, high-tide and low-tide effects are each applied by half. The GM signals a transition interval with clues such as "the wind clears" or "the incense leans."

#4. Seasonal Great Tides

#Dividing the Seasons

The Spirit Realm follows the same seasonal cycle as the domain: spring, summer, autumn, and winter. Each season lasts about 90 days. Each season also has a peculiar period called a "great tide(大潮)," during which tide effects are amplified.

#Spring Great Tide — Pressure Period

The spring great tide is called the "pressure period(壓期)." All high tide effects are strengthened, and Barrier Target Number increases up to +3. Among domain residents, those with high spiritual sensitivity show symptoms of anxiety during this period. Scenario setup: a time when incidents inside the domain are amplified by influence from outside the barrier.

#Summer Great Tide — Exposure Period

For 7 days around the summer solstice, low tide becomes extremely deep. At deep low tide, barrier Target Number falls as far as -3. Paradoxically, this is the "golden season of Spirit Realm exploration": Exposure increase is reduced, and barrier crossing is easy. At the same time, there is the coexisting danger that an important yoma may infiltrate the domain through the weakened barrier.

#Autumn Great Tide — Dipole Period

For 21 days after the autumn equinox, both high tide and low tide become extreme. Within one koku, barrier Target Number can swing from +3 to -3. This instability is the most dangerous period in the Spirit Realm, and yoma activity reaches its yearly peak. It is often used as a campaign climax season.

#Winter Great Tide — Stillness Period

For 9 days around the winter solstice, the tide seems to stop. There is no high tide or low tide, and barrier Target Number remains at its baseline value. This stillness itself is an omen: something vast is preparing outside the barrier. During the stillness period, incense does not sway at all. The GM holds this silence for a long time, planting in the players the premonition that "something is approaching."

#Great Tide Checklist

The GM marks great tide periods on the campaign calendar in advance. When scenarios are placed around great tides, the environment itself creates the rhythm of the drama.

#5. Moon Phase — The Direction of the Tide

#The Moon's Presence

The Spirit Realm also has a moon. It appears in the same shape as the moon seen from the domain, but its light is not silver-gray; it is a pale blue. The moon phase follows a 29-day cycle.

#Moon Phase and Direction

The moon phase determines the "direction" from which the tide flows in. At high tide, the pressure applied to the barrier is not from every direction, but focused from a specific direction.

The correspondence between moon phase and hell is not coincidence. Each hell breathes in time with a specific phase of the moon. This correspondence is detailed under each hell entry in 03-06 Hell Guide.

#Effects of the Focused Direction

In the focused direction determined by the moon phase, high tide effects are amplified.

If the PCs explore northern Reviving during the full moon, Barrier Target Number at high tide is baseline + 2 + 1 = baseline + 3. The total Exposure modifier is +2. This is extremely dangerous. Put another way, to see that hell's true face, they must go precisely during this period.

#No-Moon(無月) Night

In the 29-day cycle, there are 1~2 days when the moon is not visible at all. This period is called "No-Moon." During it, pressure focuses on no direction; instead, weak pressure is applied simultaneously from all directions. Barrier Target Number +1 applies during every time slot.

In scenario terms, No-Moon is a day when "anything could happen anywhere." It is a good time for the GM to place many small incidents at once.

#6. Tide Prediction — PC Observation

#Prediction Check

If a PC wants to predict the tide, use a Perception check, Target Number 10. On a success, they know the timing and state of the next tide transition. During a great tide period, the check increases to Target Number 11.

Spending one stick of incense on the check gives Target Number -2. Incense is the oldest tool for reading the tide.

#Tide Records

Some PCs, such as scholars, priests, and long-term explorers, keep records of the tide. If the campaign introduces this habit, the players begin to treat "is today high tide or low tide?" as drama in itself.

The GM can provide a simple tide calendar as a session handout. Structure:

[Month N, Day N]
Tiger koku (3-7): first high tide
Snake koku (9-13): mid tide
Monkey koku (15-19): second high tide
Boar koku (21-1): deep low tide
Moon phase: full moon → north(Reviving) focus
Special: no great tide

#7. Tides and Scenario Design

#Tide-Centered Scenario

Example structure for a short scenario built around a single tide as its central gimmick.

Scenario "The Gap at Deep Low Tide"

• Setup: during the summer great tide, barrier Target Number falls to -3 at deep low tide.
• Situation: a Black Rope yoma infiltrates the domain through this gap. The PCs must reinforce the barrier before the infiltration, or pursue the yoma after it slips in.
• Time pressure: deep low tide lasts 4 hours. Everything must end within this window.
• Climax: just before second high tide arrives, the barrier strengthens again, and the yoma is either trapped inside the domain or retreats to the Spirit Realm.

#Tide-Rhythm Campaign

A method that uses the great tide cycle of a long campaign as its season structure.

• 1~3 sessions: spring pressure period — domain incidents intensify, barrier defense strengthens
• 4~6 sessions: summer exposure period — Spirit Realm exploration begins in earnest, depth is secured
• 7~9 sessions: autumn dipole period — climax, decisive battle with major yoma
• 10 sessions: winter stillness period — conclusion, epilogue, waiting for the next great tide

The natural calendar creates the rhythm of the story for you.

#8. The Poetic Dimension of Tides

#Tide and Emotion

The tide resonates with the PCs' emotions. A PC who is anxious at high tide becomes more anxious; a PC who is calm at low tide becomes calmer. This resonance is not a rule effect, but a description guideline.

When the tide changes, the GM may ask a PC's player, "How do you feel right now?" The answer is justified through the state of the tide. The player's emotion and the Spirit Realm's state move within the same sentence.

#Fear of Quiet

Low tide, especially deep low tide and the winter stillness period, can be designed to be more frightening than high tide. Low pressure means that the resistance holding something back has vanished. PCs can walk freely at low tide, but that freedom is the trap.

#Staging Tips

#Scent — The Moment of Tide Transition

When the tide changes, the GM describes the incense smoke first. "The incense stops for a moment. The smoke changes its angle. The direction reverses." Those three sentences are enough to complete each transition. Declare the sensation before declaring checks or numbers.

#Law — Running Tide Checks

At the start of the session, the GM notes the current koku and tide state. Time advances automatically according to checks and movement. When the GM decides one koku(4 hours) has passed, switch to the new state and notify the players with sensory description. It is better to express this through description than through explicit time tracking.

#Staging Tip — The Weight of High Tide

During high tide, mix the texture of "heavy" into every description. The air is heavy, the feet are heavy, the incense is heavy, the barrier is heavy. Repeating the same word creates a kind of ritual effect. Players feel high tide through the pressure of language.

#Staging Tip — The Moon's Visibility

The PCs do not need to be told that the moon phase determines the focused direction. Instead, mention once during the session that "tonight's moon is full," then show through events that the north becomes more dangerous that night. After a few sessions, the players discover the rule on their own.

#Connection — Resonance With Weather

Tides are independent of weather(03-04), but extreme tides (great tides) trigger certain weather. Example: during the autumn dipole period, the chance of a spiritual storm is 2 times higher. When the two systems intersect, the session reaches its highest intensity.

#9. Tides and PC Sensation — Detection Steps

PCs detect the tide in several steps. These steps operate regardless of the PC's spiritual sensitivity, and apply equally to all PCs.

#Perception Steps

1. Feel it on the skin — a change in the weight of the air. The earliest sense. About 10 minutes before high tide.
2. Confirm with incense — confirm tide direction through the angle of incense smoke. Perception check, Target Number 8.
3. Color of the barrier dome — when viewing the dome from a distance, confirm the tide step through color change. Target Number 10.
4. Reaction of the surrounding scenery — the reaction by which hell weather is amplified at high tide. Target Number 11.

The GM consciously moves the PCs' perception of the tide through these steps. "The skin knows first → incense confirms → the scenery answers."

#Tide Sense and State

PCs with high Exposure feel the tide more sensitively, paradoxically: those who are stained resonate with the environment. PCs with Exposure 7 or higher get -2 to detection checks, making detection easier. Conversely, Clear PCs at Exposure 0 get +2, making detection harder.

This paradox expresses a consistent theme of Spirit Realm rules: the more one becomes part of the Spirit Realm, the better one feels the Spirit Realm.

#10. Special Tide States

#Tidal Disturbance(潮撹)

A rare abnormal phenomenon. The tide cycle is disrupted, so high tide and low tide mix, or the sequence proceeds in an order different from prediction.

Trigger Conditions:

• Major barrier shock (mass yoma incursion, failed barrier ritual, etc.)
• Accompanied by a spiritual storm
• Collision during a great tide period (example: spiritual storm during the autumn dipole period)

Effects:

• Tide prediction checks impossible (for 1~3 days)
• Barrier Target Number changes every round by rolling d10: 1~5 gives -3 / 6~10 gives +3
• Movement rounds +1
• Exposure modifier +1

Tidal disturbance is used as a dramatic crisis situation in the campaign. The moment predictable tides collapse, the balance of the entire Spirit Realm shakes.

#Tide Halt(潮止)

An extremely rare phenomenon. The tide stops completely for several days. Barrier Target Number is fixed at its middle value.

Trigger Conditions:

• Peak of the winter stillness period
• A specific sealing rite
• Interference by a supreme yoma presence

Effects:

• All tide-related modifiers are nullified
• During this period, barrier checks use the baseline value
• Strange sensations inside the domain (several residents share an ominous premonition at once)

Tide halt is an event that may appear once or twice at most in a very long campaign.

#11. Calendar and Session Operation

#Creating a Tide Calendar

Before the campaign begins, the GM creates a tide calendar. Record tide states by real-world date.

Recommended format:

[Divine Calendar Month N, Day N, Tuesday]
Session: No. N
Tiger koku (3-7): first high tide
Snake koku (9-13): mid tide
Monkey koku (15-19): second high tide [moon phase: full → north focus]
Boar koku (21-1): deep low tide

Great tide: none (next great tide in 12 days)
Special: [GM memo]

Consult this calendar before the session, and plan in advance which tide time slot will hold each scene in the session.

#Player-Shared Calendar

A simplified calendar may be shared with the players. Items:

• Day of the week and time slot
• Tide high/low state (numbers hidden)
• Known great tide periods

When players read the calendar, they begin planning strategic timing within the session. Conversations like "let's cross the boundary zone at deep low tide" arise naturally.

#Mapping Session Time to Tide Time

An actual session is usually 3~4 hours. Decide which koku the internal flow of the Spirit Realm will cover within that time. Recommended mapping:

Long-stay Spirit Realm scenarios proceed across multiple sessions. Record how the tide cycle advances during the intervals between sessions.

#12. Tides and Hells — Interaction

Each hell becomes most active during a specific tide time slot. Apart from moon phase, the tide koku itself has a hell resonance.

#Tide Resonance by Hell

Use this table when designing scenarios in a long campaign. If you want to emphasize a particular gimmick of a particular hell, place the scene in that tide time slot.

#Narrative Use of Tide Resonance

If the PC party wants an intense experience of Reviving's Cadence of Revival, design a journey that reaches the Reviving Central Hall at second high tide(just before sunset). Tide, hell, and story meet at a single point.

#13. Tide Rite — Expansion of Incense Rites

#Structure of a Tide Rite

Skilled PCs, such as monks, miko, or sorcerers, can perform a tide rite. The rite is an attempt to locally adjust the flow of the tide.

Rite Structure:

1. Light 3 sticks of incense simultaneously
2. Mental Save, Target Number 13
3. On success: within a radius of one round, reverse tide effects by 1 step (high tide → middle, low tide → middle, etc.)
4. Duration: one koku(one cycle among the four in a day)
5. On failure: Exposure +2, trigger tidal disturbance

#Rite Dangers

Even a successful rite has a cost. Because the act resists the natural flow of the tide, the rite performer receives Exposure modifier +1 throughout the next tide cycle.

PCs who perform the rite repeatedly will have increasing difficulty managing Exposure over the long term. This structure reflects the design principle that powerful force has a cost.

#Narrative Meaning of the Rite

A tide rite is a rare means by which a PC can "speak" to the laws of the Spirit Realm. Usually, PCs are in the position of following the Spirit Realm's rules, but through the rite they can influence those rules. This moment can become an important turning point in the campaign.

#Staging Tips

#Scent — The Moment of Tide Transition

When the tide changes, the GM describes the incense smoke first. "The incense stops for a moment. The smoke changes its angle. The direction reverses." Those three sentences are enough to complete each transition. Declare the sensation before declaring checks or numbers.

#Law — Running Tide Checks

At the start of the session, the GM notes the current koku and tide state. Time advances automatically according to checks and movement. When the GM decides one koku(4 hours) has passed, switch to the new state and notify the players with sensory description. It is better to express this through description than through explicit time tracking.

#Staging Tip — The Weight of High Tide

During high tide, mix the texture of "heavy" into every description. The air is heavy, the feet are heavy, the incense is heavy, the barrier is heavy. Repeating the same word creates a kind of ritual effect. Players feel high tide through the pressure of language.

#Staging Tip — The Moon's Visibility

The PCs do not need to be told that the moon phase determines the focused direction. Instead, mention once during the session that "tonight's moon is full," then show through events that the north becomes more dangerous that night. After a few sessions, the players discover the rule on their own.

#Staging Tip — Fear of Stillness

When staging the "nothing happens" of deep low tide or the winter stillness period, the GM deliberately shortens sentences. "The incense burns down. The barrier is there. Nothing happens." The short breath of these three sentences creates the fear of quiet.

#Connection — Resonance With Weather

Tides are independent of weather(03-04), but extreme tides (great tides) trigger certain weather. Example: during the autumn dipole period, the chance of a spiritual storm is 2 times higher. When the two systems intersect, the session reaches its highest intensity.

#Links

• Previous: 03-02 Travel Rules
• Next: 03-04 Weather Hazards
• Topology Reference: 03-01 Spirit Realm Topology
• Events: 03-05 Boundary Events
• Moon Phase and Hell Correspondence: 03-06 Hell Guide
• Core Barrier Target Number Source: 05-05 Zone Gimmicks