Designing Tairyō: what a slot’s paytable is actually promising you

The shape of the machine

Tairyō (大漁, “big catch”) is a fishing-themed reel game: five reels, three rows, ten fixed paylines. That geometry is the first thing worth understanding, because it sets everything else.

Ten fixed lines rather than a “ways” model means a symbol pays only when it lands on one of ten specific paths across the reels. Three of those paths are the straight rows; the rest zig-zag. A screen can be visually full of a symbol and pay nothing at all, because none of the ten paths happened to cross it.

The cap is the part most paytables leave you to work out. A published maximum is a promise about the worst case for the house, and its existence is why a paytable’s headline figure is bounded rather than theoretical.

The rule that explains the near-misses

Lines pay left to right, beginning at reel one. A run of four matching symbols on reels two through five pays exactly nothing, no matter how it looks.

This single rule generates most of a slot’s felt experience. The eye reads a screen for clusters; the engine reads it for runs anchored at the left edge. The gap between those two readings is the near-miss, and it is not manufactured — it falls out of an ordinary evaluation rule applied to a random screen.

It also explains why reel one matters disproportionately. Every paying combination on every line begins there, so the composition of that reel does more to shape the game’s behaviour than any other.

The paytable, and where the money really is

Here is the table, with factors expressed as multiples of the line bet — the number a single payline stakes, which on ten lines is a tenth of your total bet.

Two things stand out. The top symbol is worth twenty times the next-best at five in a row, which is where the drama lives — and the bottom five symbols are worth the same as each other, which is where almost all the actual hits live.

That bottom row is the honest answer to “how does this game feel”. Card ranks paying ×0.5 for three of a kind means a large share of winning spins return less than the spin cost. The counter ticks up, the sound plays, and the balance goes down. Every reel game does this; it is worth knowing that it is the design rather than an unlucky streak.

Why the collector exists

The line pays above are not the reason anyone plays this kind of game. The feature is: money symbols land carrying values, and a collector sweeps every value on screen at once.

The design logic is that a collector converts a spread of small values into one large event. Three ×5 fish are forgettable; three ×5 fish and a collector is a story. Nothing about the underlying values changed — only whether they arrive together.

That is a deliberate variance trade, and it is the honest way to describe every slot feature: features rarely add return, they redistribute it, taking value out of ordinary spins and concentrating it into rare ones. A game with a big feature is a game whose base game is quieter than it would otherwise be.

How to read any paytable in thirty seconds

The habit generalises well beyond our game.

1. Find the cap first. It bounds everything and is often the only figure that limits the headline.
2. Look at the bottom of the table, not the top. Those are the outcomes you will actually see, and if three-of-a-kind pays less than the spin, you now know what most wins will feel like.
3. Check whether wins are left-to-right or “ways”. It changes what a full-looking screen is worth.
4. Count the lines, then divide your total bet by them. That is the number the paytable is quoting against — a factor of ×200 on a line bet is not ×200 of your stake.