Four Rivers Mahjong: Game Description & Official Manual

Part I: Game Description

1.1 Overview and Lore

Embark on a serene journey through the ancient waterways of the East in Four Rivers Mahjong (traditionally known in oriental card and tile puzzle heritage as Shisen-Sho or Rivers Mahjong), an elegant and highly tactical tile-matching puzzle game rooted in spatial pathfinding and visual discipline. Set against the misty, river-carved valleys of the Yangtze, Pearl, Yellow, and Amur rivers, players step into the sandals of a master river navigator charting ancestral waterways. To clear the ancient stone channels, unlock forgotten temple vaults, and restore harmony across the land, you must connect matching pairs of traditional mahjong tiles using clear line-of-sight paths that bend no more than twice across open space.

In Four Rivers Mahjong, classic tile-matching dynamics are transformed into a dynamic line-connecting strategy challenge. Unlike standard mahjong solitaire—which focuses on dismantling multi-layered stacked pyramids by removing tiles unblocked along their lateral edges—Four Rivers Mahjong presents a sprawling single-layer rectangular grid of 144 tiles laid flat across an ornate bamboo board. Matching pairs are cleared not simply by locating identical suits, but by mapping an unobstructed connection route—a "river path"—between them. The line connecting the two tiles can travel across empty board space, around outer board perimeters, or through cleared channels, provided the path turns at right angles ($90^\circ$) no more than two times.

Designed for puzzle purists, visual strategists, and casual gamers seeking a deeply meditative yet intellectually stimulating experience, Four Rivers Mahjong balances intuitive point-and-click or tap controls with escalating geometric foresight. Every pair cleared carves a fresh open channel into the grid, opening up interior access to previously trapped tiles or creating dead-end blockades if executed without long-range planning. Featuring crisp tile-snapping animations, tranquil oriental acoustic soundscapes, strategic wildcards, and hundreds of river stages, Four Rivers Mahjong delivers a captivating puzzle journey where visual clarity and pathfinding precision guide your way to victory.

1.2 Component Inventory & Waterway Interface Layout

Whether played via precision mouse controls on desktop systems or intuitive touch gestures on mobile devices, Four Rivers Mahjong features a sleek, high-contrast digital interface styled after an antique lacquered wood navigation table:

1 Central Navigation Grid (The River Table): A flat $12 \times 12$ rectangular board matrix holding 144 traditional mahjong tiles laid face-up in a single flat plane:
- Grid Boundaries: The open empty space surrounding the outer edges of the tile layout serves as a valid "outer river" path for line-connecting moves.
- Interior Channels: Empty spaces created within the grid as tiles are matched and removed, forming expanding internal waterways.
1 Traditional 144-Tile Mahjong Set: Composed of authentic suit suits and honor tiles:
- Suits (36 Tiles Each): Bamboo (1–9), Characters (1–9), and Dots/Coins (1–9).
- Honors (28 Tiles Total): Four Winds (East, South, West, North) and Three Dragons (Red Dragon, Green Dragon, White Dragon).
- Specialty Wildcards (8 Tiles Total): 4 Season Tiles (Spring, Summer, Autumn, Winter) and 4 Flower Tiles (Plum, Orchid, Bamboo, Chrysanthemum).
1 Navigator Utility Rack (Power-Up Bar): A bottom utility panel holding essential navigation tools:
- River Compass (Hint): Highlights a valid matching pair currently connectable under the 2-Turn Rule.
- Current Shuffle: Rearranges all remaining tiles on the grid to create fresh pathfinding opportunities.
- Bending Reed (Undo Move): Reverses your last tile match, placing the pair back onto the grid.
- Explosive Firecracker: Instantly blasts away any chosen pair of identical tiles regardless of path obstruction.
1 Celestial HUD Bar: An integrated top monitoring panel displaying real-time navigation metrics:
- River Flow Timer: Tracks remaining stage time or move limits.
- Open Pair Counter: Displays the exact number of legal matching pairs currently available on the board.
- Dragon Medal Rating: Evaluates clearing speed and pathfinding efficiency to award 1 to 3 Medals upon level completion.

1.3 Visual Aesthetics and Eastern Atmosphere

Four Rivers Mahjong surrounds players with a peaceful, authentic visual and auditory atmosphere designed to promote deep focus and mental clarity:

Lacquered Oriental Artistry: High-definition tile graphics featuring rich bone-and-bamboo textures, crisp brush stroke calligraphy, dynamic water ripples, and soft lantern light casting gentle reflections across dark polished wood tables.
Dynamic Path Effects: Connecting valid tile pairs draws a glowing line of liquid light along the calculated river path, accompanied by soft water splashes, rising mist particles, and a crisp wooden clack as the tiles vanish.
Acoustic River Soundscape: A soothing, meditative soundtrack driven by traditional Chinese zithers (guzheng), bamboo flutes (dizi), soft pipas, and ambient natural water sounds like trickling streams and distant rain.

1.4 Core Objectives

The primary objective in Four Rivers Mahjong is to clear every single tile from the navigation board by connecting all identical pairs using valid river paths before time expires or no legal moves remain.

Player performance and pathfinding efficiency are evaluated through:

Grid Liquidation: Removing $100\%$ of the 144 tiles from the board matrix.
Path Minimization: Clearing tiles using short, direct $0$-turn or $1$-turn paths to earn extra accuracy bonuses.
Combo Streak Execution: Connecting consecutive tile pairs within $3$ seconds of each other to activate score multipliers.
Dragon Medal Maximization: Earning 3 Dragon Medals on every stage by clearing boards rapidly without using manual shuffles.

Part II: Gameplay Instructions

2.1 Core Mechanics & The Two-Turn Path Rule

Mastering Four Rivers Mahjong requires a complete understanding of line-of-sight pathfinding, right-angle turns, and wildcard matching rules.

Law 1: The Two-Turn Rule (The 2-Bend Path Limit)

Two matching face-up tiles can only be selected and cleared if a continuous path can be drawn between them through empty grid spaces or around the outer perimeter of the board.
The connection path consists of straight horizontal ($\text{H}$) and vertical ($\text{V}$) line segments meeting at $90^\circ$ right-angle corners.
Maximum Bends: The path may contain a maximum of two $90^\circ$ turns (3 line segments maximum).

$$\text{Valid Path} \iff (\text{Turn Count} \le 2) \land (\text{All Path Segments Clear of Tiles})$$

Path Classification Types:
- Direct Path (0 Turns / 1 Line): Tiles sit in the same row or column with no intervening tiles between them ($\text{Tile A} \longrightarrow \text{Tile B}$).
- L-Shape Path (1 Turn / 2 Lines): Path makes a single right-angle corner in empty space ($\text{Tile A} \longrightarrow \llcorner \longrightarrow \text{Tile B}$).
- Z-Shape or U-Shape Path (2 Turns / 3 Lines): Path turns twice, weaving around obstacles or traveling along the outer border ($\text{Tile A} \longrightarrow \ulcorner \longrightarrow \lrcorner \longrightarrow \text{Tile B}$).

Law 2: Standard and Wildcard Matching

Standard Matches: Select two identical tiles belonging to the same suit and number (e.g., two identical $5$-Bamboo tiles).
Season Wildcards: Any Season tile (Spring, Summer, Autumn, Winter) matches with ANY other Season tile, regardless of specific season artwork.
Flower Wildcards: Any Flower tile (Plum, Orchid, Bamboo, Chrysanthemum) matches with ANY other Flower tile.

Law 3: Outer Border Exploitation

The empty boundary surrounding the tile grid acts as an infinite open waterway.
Tiles located along the outer edges of the grid can connect to other outer-edge tiles by sending a path outward into the empty border, traveling along the exterior, and turning back inward!

Select River Region: Choose an active waterway node from the World Map (e.g., Yangtze Mist, Yellow River Falls, Pearl Delta, or Amur Frost).
Board Deal: The game engine deals 144 tiles face-up in a single flat rectangular matrix, verifying that a solvable path configuration exists.
Review Briefing: Check stage limits on the scroll board (e.g., "Clear 144 Tiles in under 300 Seconds").
Navigation Start: The level timer initializes and the board unlocks as soon as the stage loads!

2.3 Fundamental Tactics & Step-by-Step Strategy

Clearing dense flat tile boards requires disciplined spatial awareness and long-range channel carving. Master navigators rely on four core tactical principles:

Technique 1: Perimeter Cleaning (Outside-In Strategy)

Always prioritize clearing matching pairs along the outer edges of the grid first! Clearing edge tiles widens the outer boundary, creating longer exterior paths that allow deep interior tiles to connect out and around the board.

Technique 2: Carving Internal Cross-Channels

Focus on clearing adjacent parallel pairs sitting inside the grid! Removing interior tiles creates open corridors across the middle of the board, breaking dense tile blocks into smaller, accessible islands.

Technique 3: Quad-Tile Set Clears

When four identical tiles are visible and accessible on the board simultaneously, match them both out immediately! Eliminating a complete four-tile set prevents orphaned tiles from getting trapped behind new obstacles later.

Technique 4: Preserving Key Turning Hubs

Avoid clearing pairs that leave an isolated, single tile sitting in the middle of a crucial intersection unless necessary. Open intersection spaces are invaluable for allowing 2-turn Z-paths to pass through the center of the board.

2.4 Structure of an Active Play Loop

Gameplay in Four Rivers Mahjong operates through a continuous four-phase puzzle-solving loop:

Phase 1: Grid Scanning & Route Calculation
- Scan the board for matching identical tiles along edges or direct lines of sight.
- Trace potential $0$-turn, $1$-turn, or $2$-turn paths through empty spaces mentally.
Phase 2: Action Execution & Path Validation
- Click or tap the first tile (highlighting it with a glowing golden frame).
- Click the second matching tile. If the pathing engine confirms a valid $\le 2$-turn route, the glowing river line flashes and both tiles dissolve.
Phase 3: Channel Expansion & Open Pair Update
- The newly emptied spaces instantly join the active waterway grid.
- The Open Pair Counter updates to reflect newly accessible matches.
Phase 4: Stage Clear or Stalemate Settlement
- Repeat matching cycles until the grid is empty to claim victory, or until no valid moves remain.

2.5 Navigator Power-Up Tools

Power-Up Tool	Visual Icon	In-Game Effect & Strategic Usage
River Compass	Brass Compass	Instantly highlights two matching tiles with a valid, connectable river path
Current Shuffle	Swirling Waves	Rearranges all remaining tiles on the board into new positions with guaranteed matches
Bending Reed	Bamboo Reed	Undoes your previous tile play, returning both tiles back to their board slots
Firecracker	Red Firecracker	Instantly destroys any selected pair of identical tiles regardless of path obstruction

2.6 Game Modes

2.6.1 River Campaign (Journey Mode)

The main story adventure featuring over 200 handcrafted layouts across historic Asian waterways, progressive obstacle introductions (e.g., locked stone tiles, frozen river blocks), and artifact collection.

2.6.2 Torrent Race (Speed Mode)

Gameplay: Race against a rapid 120-second expedition clock!
Mechanics: Every successful match adds $+3$ bonus seconds to your running timer. The goal is to clear as many tile pairs as possible before the flood arrives.

2.6.3 Zen Waterway (Relaxed Mode)

A calm, unhurried mode with no timers, infinite hints, unlimited manual shuffles, and ambient zither music. Perfect for meditative, stress-free puzzle solving.

2.7 Scoring & Performance Settlement

Upon completing a river navigation stage, your efficiency is calculated on the Navigator’s Log:

$$\text{Final Score} = \text{Base Pair Points} + (\text{Remaining Seconds} \times 150) + (\text{Max Combo Streak} \times 300)$$

Base Pair Value: $+100$ Points per cleared tile pair.
Path Efficiency Bonus: $+50$ Extra Points for direct $0$-turn or $1$-turn path matches.
Speed Bonus: $+150$ Points for every unused second remaining on the level clock.
Dragon Medal Ratings:
- 1 Medal: Clearing all 144 tiles before time expires.
- 2 Medals: Clearing the board with $>30\%$ time remaining and zero shuffles.
- 3 Medals: Master Navigator! Flawless clearance with $>60\%$ time remaining, high combo streaks, and zero power-ups used!

2.8 Game End & Victory Conditions

A playthrough of Four Rivers Mahjong officially terminates upon reaching either of two final navigation states:

Waterway Cleared (Victory): Every single tile is successfully matched and removed from the board. Lotus blossoms bloom across the water, awarding gold coins, dragon medals, and unlocking the next river stage on the map!
Stalemate / Time Expired (Defeat): Occurs if the timer reaches zero while tiles remain, or if no valid $\le 2$-turn paths exist and the player has zero shuffles left. Players can retry the stage or spend gold coins to trigger a board shuffle and continue.

The navigator who completes all campaign stages with 3-Dragon Medal ratings earns the ultimate title of Grand Master of the Four Rivers!

2.9 Field Rules & System Integrity

Deadlock Auto-Detection: If no legal $\le 2$-turn matches remain among active tiles, the system alerts the player and offers a free shuffle prompt to prevent unwinnable stalemates.
Auto-Save Checkpointing: Active board layouts, earned coins, unlocked tile styles, and medal ratings save automatically after every move.
Cross-Device Cloud Sync: Campaign progression, unlocked river maps, and high-score rankings sync seamlessly across desktop, tablet, and mobile platforms.

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Four Rivers Mahjong