In two sentences: Three Scatters award eight free spins with boosted coin and Boost frequency, while six or more coins open the Hold and Win respin round. A random Treasure Chest Feature can also force the bonus open from a single coin landing in the base game.
The extra features in Pirate Chest run on a multi-tiered loop that links base game spins, Scatter-triggered free spins and the Hold and Win respin mechanic. Landing three pirate ship Scatters on reels 1, 3 and 5 unlocks eight free spins. During that phase, additional coin symbols and octopus Boost icons are added to the reels, which lifts the probability of activating the primary bonus round. Land three or more Scatters again inside free spins and you receive a further eight, extending the enhanced-frequency phase.
Beyond the standard triggers, Pirate Chest includes a random base-game modifier called the Treasure Chest Feature. Whenever at least one gold coin Bonus symbol lands during a standard spin, it can randomly trigger the Treasure Chest animation. Once activated, the feature adds enough extra Bonus symbols to the grid to launch the Hold and Win respin round on the spot. In practice, a spin that looks like a near miss with one or two coins visible can convert into a full bonus entry without warning. It is one of the few mechanics here that rewards ordinary low-coin spins.
The Hold and Win respin feature is otherwise triggered when six or more gold coin symbols, or five coins combined with a Boost symbol, land simultaneously anywhere on the grid.
Once you enter Hold and Win, standard symbols fade away and only gold coins, Boost icons and blank spaces remain on a dedicated 5x4 grid. You start with three respins. Every new coin that lands becomes sticky, locks into position and resets the respin counter back to three. Special mystery coins can transform into fixed jackpot symbols: Mini (20×), Minor (50×) or Major (100×). Cover all 20 grid positions with coins before the respins run out and the Grand jackpot of 3,000× the stake is added on top of every accumulated coin value, which caps the theoretical maximum win near 3,589×.
That distinction matters when you compare marketing claims across casino lobbies. Some operators advertise the ceiling as a flat 3,000×, and that describes only the Grand Jackpot component. The full theoretical maximum of 3,589× reflects the Grand Jackpot plus the coin values already locked on a fully covered grid.