How to Play Single-Line Slots Online

What a Single-Line Slot Is

A single-line slot pays on one pattern of symbols, conventionally the row across the centre of a three-reel grid. The format predates video slots and is still built: Push Gaming describes its own Bait 'n' Bank as a three-by-three classic-style slot. The Gambling Commission's remote technical standards define slots broadly as casino games of a reel-based type, including games with non-traditional reels, so a one-line game falls under the same rules as any other online slot.

What a Payback Percentage Does and Does Not Tell a Player

A return-to-player or payback percentage describes the long-run design of a particular game. The Commission's consumer guidance states that the percentage is an average achieved over a significant number of game plays and not each time the game is played, and gives the warning directly: if a gaming machine displays an 85% RTP, a player should not expect to win an average of 85 pence for every £1 staked during a playing session. Its guidance for licensing authorities puts the scale on which a fully random game converges on its figure in the order of a million or more game cycles.

The figure is also per game. The Commission states that there is no statutory minimum %RTP figure and that, for machines hosting several games, each separate game must state and meet its own individual figure. There is no payback percentage for single-line slots as a category, and the one that matters is the one shown in the game being played.

The Simplicity Is in the Paytable, Not the Maths

One payline means a short paytable, and the Commission's standards require that an explanation of the applicable rules is easily available before a customer commits to gamble, with content that is accurate and sufficient to explain all of the applicable rules and how to participate. A reader can realistically check every winning outcome on a single-line game, which is harder on a game with many lines or a changing number of ways. That is a difference in how legible the game is, not in how much it returns.

Fairness Does Not Depend on Being Able to Follow the Game

A game that is hard to follow is not therefore unchecked. All gambling products must be tested by an approved test house before release, and online gambling games cannot be made available to players located in Great Britain unless sufficient testing has been carried out. Once a game is live, operators are required to check the performance of the games they offer to make sure they are fair and achieving the designed return to player. The standards also require that games are implemented fairly and in accordance with the rules and prevailing payouts as described to the customer.

Fixed and Progressive Jackpots

A single-line game may carry a fixed top prize set out in the paytable, or a progressive jackpot funded from stakes. Where it is progressive, the Commission's requirement is that an explanation of the jackpot rules must be clearly available to the customer before they commit to gamble; its implementation guidance for that requirement, which is guidance rather than a rule, says those rules shall describe how the jackpot is funded and what the start-up seed and any ceiling values are, and that the jackpot system's return-to-player percentage should be displayed as per RTS 3C, either as one combined figure or broken down into the base game and the jackpot component — with the obligation to publish an RTP at all coming from RTS 3C itself rather than from the jackpot standard. Where a jackpot is capped at a ceiling value, an explanation of how subsequent player contributions are handled should be provided.

No Pattern to Read

The standards require game results to be acceptably random and prohibit adaptive behaviour, meaning interventions that change the probabilities of game outcomes during play, and the Commission's consumer guidance states that on a random machine the odds of achieving a win in the current game remain constant and are not affected by wins or losses in previous games. A short run of blanks on a three-reel game carries no more information than it would on any other slot.