Whale Isle Sugoroku
The board-game machine of the medal floor: roll the die, sail the boat round the island, and ride the whale to the jackpot.
The board: 30 squares round Whale Isle. The boat is on square 0: START.
Choose
What the squares do
- START: sailing past pays ×½
- Shell: ×½
- Pearl: ×1
- Palm tree: a rest
- Tailwind: on that many squares
- Ebb tide: back that many squares
- Storm: back that many squares
- Whirlpool: back to START
- Lamp Chance: ×1 to ×10
- Whale Ride: the bonus: 3 free rolls
- JP Chance: a 6 at the JP final is ×100
Keys: Space or Enter rolls (or skips) · S skips · B changes the bet
Medals are for playing the games on this site only. They are not money: they cannot be bought, cashed out or exchanged for anything.
Your medals are the Medal Game Center’s, shared by every machine there. Daily bonus and refills at the front
Last rolls
No rolls yet.
This visit
- Rolls
- 0
- Medals played
- 0
- Medals won
- 0
- Net
- 0
- Whale rides
- 0
- Jackpots
- 0
- Came back
- —
- Steady play returns
- 89.74%
Every figure here is worked out exactly, in fractions, not by playing. Where the boat stands is all that carries from one roll to the next, so the machine is a chain of 30 squares: for each square, every way a roll from it can go (the die, the lamps, the JP final and the whale’s three rolls: 93,312 ways in all) gives what the roll brings back and where it leaves the boat.
You can see where the boat is before you choose your bet, so no square may be one where betting big wins in the long run: from every square, the next roll brings back less than it takes.
The rules this machine plays by
- The die: one six-sided die, each face 1 chance in 6, every roll. The roll is drawn the moment ROLL is pressed.
- The board: 30 squares in a loop. The boat stays where it stops until the next roll, through a reload or another tab; a reset at the medal center puts it back at START.
- The bet: 2, 4, 6 or 10 medals a roll. Every figure is per 2 medals bet.
- The lap bonus: ×½, for sailing past START or onto it, but not for the whirlpool’s trip back to it.
- An arrow (a tailwind, the ebb tide, the storm, the whirlpool) moves the boat once; the square it reaches then counts.
- The chances and the whale ride are part of the roll that starts them: they take no medals of their own.
Every square
| Square | What it is | Next roll brings back | Boat there |
|---|---|---|---|
| 0 | START | 67/7293.06% | 7.05% |
| 1 | Shell | 67/7293.06% | 3.37% |
| 2 | Pearl | 67/7293.06% | 3.62% |
| 3 | Palm tree | 67/7293.06% | 8.00% |
| 4 | Shell | 67/7293.06% | 4.47% |
| 5 | Shell | 67/7293.06% | 4.82% |
| 6 | Lamp Chance | 67/7293.06% | 5.22% |
| 7 | Tailwind → 10 | — | — |
| 8 | Pearl | 67/7293.06% | 4.36% |
| 9 | Storm → 3 | — | — |
| 10 | Shell | 67/7293.06% | 8.06% |
| 11 | Shell | 67/7293.06% | 3.74% |
| 12 | Whale Ride | 67/7293.06% | 3.56% |
| 13 | Shell | 67/7293.06% | 7.21% |
| 14 | Pearl | 67/7293.06% | 4.49% |
| 15 | Whirlpool → 0 | — | — |
| 16 | Shell | 67/7293.06% | 4.51% |
| 17 | Ebb tide → 13 | — | — |
| 18 | Lamp Chance | 67/7293.06% | 3.30% |
| 19 | Shell | 67/7293.06% | 3.25% |
| 20 | Tailwind → 26 | — | — |
| 21 | Palm tree | 67/7293.06% | 1.84% |
| 22 | Shell | 67/7293.06% | 2.15% |
| 23 | Shell | 67/7293.06% | 1.76% |
| 24 | JP Chance | 1/250.00% | 2.05% |
| 25 | Shell | 7/1258.33% | 1.84% |
| 26 | Pearl | 2/366.67% | 4.20% |
| 27 | Palm tree | 3/475.00% | 2.31% |
| 28 | Shell | 5/683.33% | 2.38% |
| 29 | Shell | 11/1291.67% | 2.42% |
What the next roll brings back from each square, per medal bet, and how often the boat stands there in the long run. Nobody stops on an arrow: it moves the boat on at once.
The chances
Each special square (a Lamp Chance, the JP Chance, the Whale Ride) is worth exactly 37/12 (×3.083) of the bet on average.
Lamp Chance: 12 lamps
| Pays | Lamps | Chance |
|---|---|---|
| ×10 | 1 | 1/12 |
| ×5 | 2 | 1/6 |
| ×3 | 2 | 1/6 |
| ×2 | 4 | 1/3 |
| ×1 | 3 | 1/4 |
JP Chance: 12 lamps and the JP final
| Pays | Chance |
|---|---|
| ×100 JP FINAL: a 6, the jackpot | 1/72 |
| ×4 JP FINAL: any other face | 5/72 |
| ×5 | 1/12 |
| ×3 | 1/6 |
| ×2 | 1/12 |
| ×1 | 1/4 |
| ×½ | 1/6 |
| No prize | 1/6 |
The JP star → JP FINAL: 1/12
Whale Ride: three free rolls
The whale’s back pays ×½ or ×1 on each of its squares; the boat reaches the blowhole, and the JP Chance, 50% of the time.
Why every square is worth the same
A roll from a square lands on one of the six squares after it, each 1 chance in 6, so what it brings back is the average of those six. The board repeats every six squares: a special square, then a shell, a pearl, a palm tree, a shell and a shell. Any six squares in a row hold one of each, so the next roll brings back the same from every square.
Every special square is made to be worth the same on average, and an arrow only ever carries the boat to a square of the kind it stands in for. The one place the six are not alike is just before START: START itself pays only its lap bonus, so the six squares before it are quieter.
The long run
How often the boat stands on each square in the long run is the chain’s stationary distribution, solved exactly: the arrows and the whirlpool send it to some squares more often than others. Steady play brings back the average of every square’s next roll, each weighted by how often the boat stands there.
Changing the bet as the boat moves cannot beat that by much: betting 10 on every square but the six before START, and 2 there, is the best any choice of bet can do, and it still brings back less than it takes.
How often, in the long run
| Something | Chance | Once in |
|---|---|---|
| A roll pays something | 84.2% | 1.2 rolls |
| Lap bonus | 9.0% | 11.1 rolls |
| An arrow moves the boat | 20.4% | 4.9 rolls |
| Lamp Chance | 8.5% | 11.7 rolls |
| JP Chance (on the board or at the blowhole) | 3.8% | 26.1 rolls |
| Whale Ride | 3.6% | 28.1 rolls |
| The blowhole | 1.8% | 56.1 rolls |
| The jackpot | 0.053% | 1,878.9 rolls |
Next to the real thing
Board-game medal machines have stood on Japanese medal floors for decades: on some, a medal through a numbered checker or a dice ball off the pusher field moves a piece round a board on the cabinet’s screen; on others a ball’s colour or a digital die decides the steps. Their squares pay medals, start a lottery or a minigame, send the piece forward or back to START, and reaching the goal or a jackpot square earns a jackpot chance that a second draw decides. Kids’ machines keep the bets small and the boards short.
This machine buys its roll with a bet, as the newest machines do, and keeps the rest: squares that pay, move the boat or start a chance, a lap bonus at START, a bonus lane, and a jackpot that a final roll of the die decides. The island, the whale and every square are the floor’s own. The figures are set so that steady play brings back about 90%, as medal machines are commonly set, and so that no square is one to bet big on.
Check it
FLOOR JACKPOT
+ 1% of every medal played goes to the floor jackpot: the site adds 1 medal for every 100 you play, on top of what you play. Nothing is taken out of it, so this machine’s own return is exactly as shown.
Each medal played is also a 1 in 150,000 chance to win the whole pool, which starts again at 1,000 medals once it is won. In the long run it brings back 1.67 medals for every 100 played, but only in the long run: most players never win it.
It is for players who are signed in and have joined the floor, on the first 20,000 medals each plays in a day (Japan time) at the linked machines, with one floor jackpot a day at most.
Like the rankings, the floor jackpot is for fun. The medals played that feed it are what players’ browsers report: the site checks each report against what that machine allows, but it cannot prove it. The draw itself is made on the site’s server, never in a browser.
Linked machines: Medal Pusher, Slot Machine, Calico Janken, Roulette & Martingale, Three Card Poker, Big Catch Harbor, Mini Turf Racing, Ball Bingo, Star Festival Big Wheel, High & Low Ladder, Moonlit Sic Bo, Whale Isle Sugoroku.