AKITSORA GAMING

Koi Pond

Look down into the pond: when two koi of a breed meet, they merge and climb toward gold.

Koi Pond is a 5×5, 20-line slot. Land 6+ koi to open the pond: cells respin, koi may stay or swim and same-breed koi merge into a higher breed.

Demo play uses virtual credits with no monetary value.

RTP
96.91%
Volatility
Medium5.89
Max win
6,000× bet
Bonus buy
47.93× bet

In-game screens

Captured straight from the running game — real boards, real wins.

Koi Pond — Base game
Base game5 reels × 5 rows, 20 paylines — a pond seen from above. Two large koi swim at the sides; the four merge bonuses are top right.
Koi Pond — Line wins
Line winsA line pays from the leftmost reel across 3 or more consecutive reels; the amount appears in the capsule.
Koi Pond — Koi pond — chain merge
Koi pond — chain mergeOne swim chains three merges into a Shōwa Sanshoku, which collects the Minor merge bonus. The badge above the pond counts the chain; the panel shows respins left, koi in the pond and the running total.
Koi Pond — Lord of Golden Scales — full pond
Lord of Golden Scales — full pondTwo golden koi meet and become the Lord of Golden Scales (total ×2); the golden splash fills all 25 cells for another ×2.
Koi Pond — Big win
Big winCapped at 6,000× the bet per round.
Koi Pond — In-game paytable
In-game paytableThe same game definition as the table on this page: the game receives it from the server, and this page reads it at build time.

Specification

Type5 × 5 paylines (20 lines, 3+ consecutive reels from the left, no Wild)
Return to player (RTP)96.91%
Bonus buy RTP96.90%
VolatilityMedium (5.89)
Hit rate25.99%
Rounds winning ≥ 1× bet18.43%
Max win per round6,000× bet
Koi-pond respins frequency≈ 1 in 121.45 spins
RTP verificationExact base game + 20,000,000 feature samples; combined RTP 96.9066%, 2σ margin ±0.0128 percentage points

Game math specifications and the paytable are read at build time from the definitions shared with the server code. See Math version for the configuration shown; confirm any other version or operator-specific settings separately.

How wins work

  • The base grid is 5 reels × 5 rows with 20 fixed paylines and no Wild.
  • A line pays when the same symbol appears on 3 or more consecutive reels from the leftmost reel; only the highest win on each line counts.
  • Koi do not pay on lines and block them: 6 or more on one spin open the koi pond (respins); the triggering spin still pays its line wins.
  • There are no lines inside the pond: at the end the values of every koi are added up, then multiplied by the Lord of Golden Scales and Full Pond bonuses.

Paytable

Values are multiples of the total bet for a line of that length: win = total bet × table value (the same numbers as the in-game paytable). There is no Wild; koi do not pay on lines and block them — their values are paid all at once when the pond settles.

Symbol3 reels4 reels5 reels
Arched bridgeHigh-pay 412.540
Shishi-odoshi (bamboo water spout)High-pay 3.51035
Water lilyHigh-pay 2.58.525
Mossy stoneHigh-pay 26.520
Ripple crestLow-pay 1.253.510
Whirl crestLow-pay 12.58.5
Wave crestLow-pay 0.8526.5
Rain crestLow-pay 0.71.655

Special symbols

Koi

Do not pay on lines and block them; each carries a value (3–20× the bet) and a breed. 6 or more on one base spin open the pond; inside it koi may stay or swim on each respin and merge with a same-breed neighbour.

Merge bonuses

One for each of the Taishō Sanshoku, Shōwa Sanshoku, Golden koi and Lord of Golden Scales: Mini 20, Minor 60, Major 200 and Pond Lord 1,000× the bet.

Lord of Golden Scales

Can only be merged (two Golden koi meeting), at most one per round. The total ×2; its golden splash fills the pond for another ×2.

Features

Opening the pond — respins

Land 6 or more koi on a base spin to open the pond. Every koi carries a value (3–20× the total bet) and a breed (base-game koi are White koi and Kōhaku). The koi stay in the pond and every other cell respins on its own, starting with 3 respins that reset to 3 whenever a new koi lands; when they run out, the pond settles.

Koi swim

The grid is a pond seen from above. On every respin each koi swims one step: it stays put, moves to an empty cell above, below, left or right, or swims into a neighbour of the same breed. Koi that land in the pond carry 2–10× the bet and are one of White koi, Kōhaku, Taishō Sanshoku and Shōwa Sanshoku.

Meet and merge

When a koi swims into a koi of the same breed, the two merge into one koi of the next breed (in the cell it swam into) and their values add up: White koi → Kōhaku → Taishō Sanshoku → Shōwa Sanshoku → Golden koi. Two Golden koi merge into the Lord of Golden Scales — at most one per round.

Chain merges

If a freshly merged koi has a same-breed neighbour, they merge again at once, and again until none is left — one swim can climb two or three breeds, and every step pays its merge bonus.

Four merge bonuses

Merging a Taishō Sanshoku pays the Mini 20, a Shōwa Sanshoku the Minor 60, a Golden koi the Major 200 and the Lord of Golden Scales the Pond Lord 1,000× the total bet. Each bonus is added to the koi it creates (and travels with it into later merges); the amounts are fixed.

Lord of Golden Scales — the golden splash

The moment two Golden koi meet, the Lord of Golden Scales leaps from the water and a golden splash fills the whole pond: every empty cell lands a koi, so all 25 cells are always filled. The Lord of Golden Scales multiplies the total ×2, and the full pond ×2 again.

Full pond and settlement

All 25 cells holding a koi is a Full Pond: the pond ends and the total is ×2. When the respins run out (or the pond fills) there is one more settling spin: the values of every koi are added up and multiplied by the Lord of Golden Scales and Full Pond bonuses — only this spin pays. Each round is capped at 6,000× the bet.

Volatility — positioning

Volatility 5.89. Hit rate 25.99% counts rounds with any win; 18.43% of all rounds return at least the stake. The base game carries about 55% of the RTP; the pond opens about once every 121.45 spins and pays everything on its settling spin. This describes the product's positioning and does not guarantee session outcomes.

Bonus buy

Pay 47.93× the bet for “Koi Pond”: the pond opens at once with 6 koi placed at random among its 25 cells (breeds and values as in the base game). The price comes from the expected value measured along the buy path (buy RTP 96.90%) and is calibrated separately from the base game.

Technical

Game codeaki_nishikigoi
Math versionnk1
TechnologyHTML5, no plug-in; one client for desktop and mobile
ViewportLandscape with proportional scaling
In-game languageTraditional Chinese (additional languages on request)
CurrenciesTWD (others can be registered on request)
IntegrationTransfer wallet (Operator API v3), launch-token redirect

Sources & verification scope

This product specification is written and maintained by its developer, Akitsora Gaming (AKI電子 in Taiwan). Measurement methods and sample information for RTP, volatility and hit rate appear in the specification table. Sampled results have uncertainty; RTP describes long-run return, not an individual player or session outcome.

Internal simulations and tests are not independent certification. We do not currently hold GLI or BMM certification reports. Supply to a market requiring third-party certification depends on completing its requirements.

See slot game development and supply for integration and supply scope, About us for development and content responsibility, or contact us for a math summary, version confirmation or a correction to this page.

The story

Fiction and adapted settings written by Akitsora Gaming for this title, including invented dialogue and events. This is not a historical or folklore reference. The rules and specification tables define the gameplay and math.

At the Dragon Gate on the Yellow River, the carp that leaps the rapids becomes a dragon.
Look down into the mountain pond: when twin brocade koi meet, they merge toward gold.

I. Terraced Ponds in the Snow Country

The prized nishikigoi of Japanese gardens did not begin in imperial palaces. In the early nineteenth century, farmers in the snowbound mountains of Niigata raised common carp in terraced hillside reservoirs to sustain their villages through the long winter. One season, a carp mottled with bright crimson scales surfaced in a quiet mountain pond. Ripples spread gently beneath the arched wooden bridge where moss-covered stones and maple leaves frame the crystal water.

Instead of putting the unusual fish into the winter cooking pot, the mountain villagers spared it and carefully bred its offspring across generations. Through patient selection in clear alpine snowmelt, snow-white skin, vermilion patches, and sumi black markings gave birth to living brocade—ornamental carp dressed in silk and gold. Every glide of crimson and gold scales beneath the water lilies brings serene harmony to the timeless courtyard pond.

II. Climbing the Lineage of Breeds

Each classic variety of brocade carp carries the name of its era: first came red-and-white Kōhaku, followed in the Taishō period by three-colored Taishō Sanshoku, then the bold black-ground Shōwa Sanshoku in the Shōwa years, and finally the postwar gleam of solid metallic Ogon gold. Ripples spread gently beneath the arched wooden bridge where moss-covered stones and maple leaves frame the crystal water.

Landing enough koi on a base spin opens the Koi Pond respins, where fish merge up that exact historical ladder—from white carp to Kōhaku, Taishō Sanshoku, Shōwa Sanshoku, and Golden koi—with each higher tier awarding its own fixed merge bonus straight onto the newly formed fish as it climbs. Every glide of crimson and gold scales beneath the water lilies brings serene harmony to the timeless courtyard pond.

III. A Pond Seen from Above

Unlike aquarium fish viewed through glass from the side, nishikigoi are bred exclusively to be admired from above at the edge of a garden pool. A connoisseur standing by the water reads the fish’s broad back like an unrolled scroll painting, judging the balance of crimson and ink black against the ripples. Ripples spread gently beneath the arched wooden bridge where moss-covered stones and maple leaves frame the crystal water.

Accordingly, this grid looks straight down into a tranquil garden pond framed by water lilies, mossy stones, arched wooden bridges, and bamboo shishi-odoshi. On every respin, koi attempt to swim into neighboring cells; whenever two of the same breed meet, they merge into the next rank and can trigger chain merges across adjacent fish. Every glide of crimson and gold scales beneath the water lilies brings serene harmony to the timeless courtyard pond.

IV. The Lord of Golden Scales

When two gleaming Golden koi meet in the same square during the respins, the water erupts as the legendary Lord of Golden Scales leaps high into the air. Its arrival awards the top Pond Lord bonus and sends a golden splash across the surface that instantly places a koi into every remaining empty cell. Ripples spread gently beneath the arched wooden bridge where moss-covered stones and maple leaves frame the crystal water.

With the entire pond now filled from edge to edge with brocade carp, the final settlement spin multiplies the combined value of every fish by both the Lord of Golden Scales multiplier and the Full Pond multiplier, turning a quiet mountain pool into a shimmering sea of living gold. Every glide of crimson and gold scales beneath the water lilies brings serene harmony to the timeless courtyard pond.

Want to spin Koi Pond yourself?

The demo needs no account — click and spin. For integration docs, the math summary or sandbox access, send us an email.

Demo play uses virtual credits with no monetary value.