AKITSORA GAMING

Nambu Iron

Sand mould, molten iron and hobnail texture — a Nambu kettle born in a cold-lit foundry.

Nambu Iron is a 6×5 tumbling slot set in a cold-lit iron foundry. 8+ matching symbols pay anywhere; casting tags trigger free spins with accumulating iron-bead multipliers.

Demo play uses virtual credits with no monetary value.

RTP
96.70%
Volatility
High11.20
Max win
5,000× bet
Bonus buy
100× bet

In-game screens

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

Nambu Iron — Base game
Base gameA 6 × 5 board. Matching symbols pay anywhere on it.
Nambu Iron — Cascading win
Cascading winWinning symbols glow red-hot and break into iron flakes and sand, new ones drop in, and a single spin can pay several times.
Nambu Iron — Free spins
Free spinsIn the kettle showroom the collected multiplier accumulates for the whole feature and applies to every later win.
Nambu Iron — Big win
Big winA single round is capped at 5,000× the bet.
Nambu Iron — Bonus buy
Bonus buyBuy straight into free spins for 100× the bet. Buy RTP is measured separately.
Nambu Iron — 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

Type6 × 5 tumble, scatter pays (no paylines)
Return to player (RTP)96.70%
Bonus buy RTP96.41%
VolatilityHigh (11.20)
Hit rate48.97%
Max win per round5,000× bet
Free spins frequency≈ 1 in 214.68 spins
Calibration sample2,240,000,000 spins, standard error 0.02%

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

  • A 6 × 5 board. 8 or more matching symbols anywhere on it pay — no paylines, no adjacency requirement.
  • Winning symbols clear and new ones drop in from above, so a single spin can chain several wins.
  • Each win = (bet ÷ 20) × symbol multiplier × active multiplier.
  • As a rule, at most 2 of the same symbol appear per column, which prevents full-column stacking and keeps clusters spread across the board.

Paytable

Values are the symbol multiplier in: win = (bet ÷ 20) × symbol multiplier × active multiplier.

Symbol8–910–1112+
Hobnail iron kettleHigh-pay 2005001000
Sand mouldHigh-pay 50200500
Pouring ladleHigh-pay 40100300
Finishing fileHigh-pay 3040240
Lump of charcoalLow-pay 2030200
FirebrickLow-pay 1624160
Hemp clothLow-pay 1020100
Kettle lidLow-pay 81880
Wooden mould wedgeLow-pay 51540

Special symbols

Casting tag (scatter)

No lines, no adjacency — 4 anywhere on the board trigger the free spins feature.

Iron bead

Counts when a win lands. Base game ×2–×20, free spins ×2–×500.

Features

Iron beads (multipliers)

Counted only when a win lands; the number on the bead's smooth centre is the multiplier. Base game ×2 – ×20. Beads on the board when a win lands are summed and applied to that cascade's win; they do not carry across cascades.

Free spins

4 casting tags award 15 spins in the kettle showroom. Beads in free spins run ×2 – ×500, and the collected multiplier accumulates for the whole feature, applying to the current and every subsequent win.

Retrigger

3 more casting tags during free spins add 5 spins, with the accumulated multiplier carried over.

Bonus buy

Buy directly into free spins for 100× the bet. Bonus buy RTP (96.41%) is measured separately from the base game.

Dry-spin rescue

After 15 consecutive rounds paying less than 1× the bet, the next spin is topped up to a cluster of 8 low-pay symbols — and so is every spin after it until a round pays at least the bet. Only completed rounds still queryable in the live system count; earlier progress may no longer be retained after a long absence. The rescued spin's bet may not exceed the lowest bet of those 15 rounds; at a higher bet that spin is not topped up. Base game only; bonus buys do not count. The RTP in the spec table assumes continuous play of this game at one bet size and includes this feature's contribution (about 2.66 percentage points).

Technical

Game codeaki_nambuiron
Math versionv96
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.

Winters in the north are long, and the foundry's charcoal never goes out — sand, iron and fire are what it takes to cast a kettle.

I. Making the mould

The caster shapes the kettle's outer mould from sand and clay, then presses the hobnail pattern into its inner wall, one point at a time, with a slender rod.

A single kettle carries hundreds of hobnails, each one pressed by hand; one crooked point and the whole mould is made again.

II. The pour

Iron heated white in the furnace is poured from the ladle into the mould's gate, sparks spilling across the floor.

The number at the centre of each iron bead is the measure of that pour (base game ×2 to ×20).

III. Opening the mould

Gather 4 casting tags and the mould splits along its gate, opening onto the paper-windowed showroom. Over the next 15 spins the multiplier keeps growing (×2 to ×500).

3 more tags add 5 more spins.

IV. The finished piece

Filed smooth, fired once more and lacquered, the kettle is lifted to the window — and the cold light slides across its hobnails one by one.

Want to spin Nambu Iron 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.