Some bonus round mechanic’s reward what has already landed on the reels rather than clearing everything and starting fresh. Symbol locks are built around that principle. When a symbol locks into position, it stays exactly where it is across subsequent spins while the rest of the reels continue spinning around it. This gives the player the benefit of a favorable landing without the risk of losing it to the next spin’s reshuffle. Symbol lock features allow free credit slot bonus rounds to carry progress forward across consecutive spins. This produces a cumulative prize structure across the full feature allocation.
Which symbols lock?
Not every symbol type locks within games using this mechanic. Symbols commonly assigned locking behavior include:
- High-value premium symbols – These appear in both base game and bonus round reel sets and carry locking behavior only when they land during the designated feature, contributing their full combination value to every respin that follows their landing.
- Wild symbols with lock function – These combine substitution capability with positional holding, meaning each spin resolves around a confirmed wild that covers any symbol type needed to complete a combination across paylines passing through the locked position.
- Feature-specific bonus symbols – These exist exclusively within the bonus round reel set and carry prize values displayed directly on the symbol face, contributing their individual value to the feature total regardless of their position relative to active paylines.
Respins and locks
Symbol lock mechanics most frequently appear within respin features rather than standard free spin rounds. The relationship between the two works through a specific sequence:
- Trigger landing – A qualifying symbol lands during base game play or at the opening of the bonus feature, locking into its position and activating the respin allocation from its starting count.
- Progressive locking – Any additional qualifying symbols landing during subsequent respins lock alongside the original, with the respin counter resetting to its full starting value each time the lock is confirmed.
- Feature continuation – The respin sequence continues for as long as each new spin produces at least one additional locking symbol before the counter reaches zero.
- Feature conclusion – The prize is calculated from all locked positions across the grid when a respin completes without any new symbol landing in a lockable position.
Prize calculation methods
The prize generated from a completed symbol lock feature depends on how the specific game calculates locked symbol contributions:
- Individual value summation – Each locked symbol carries a prize value displayed on its face, with the feature’s total representing the combined sum of every locked position’s individual value at the point the feature concludes.
- Payline combination assessment – Locked symbols contribute to combination counts across active paylines, with the prize determined by the highest outcomes achievable from confirmed locked positions combined with the final respin’s non-locked results.
- Multiplier application – Multiplier symbols that lock into position apply their displayed value to the total prize accumulated from all other locked symbols, scaling the feature’s return in proportion to the multiplier confirmed at that grid position.
Symbol locks give bonus rounds a progressive quality where each additional locked position advances the feature’s potential prize forward rather than leaving the full outcome to a single spin’s result.
