Five reels, a book and one chosen symbol
On the Dukat.bet slots page, the Books tab collects games built on the same frame. The book symbol has two jobs: as a wild it substitutes for other symbols, and as a scatter it triggers the free spins. At the start of the round the game draws one symbol, and from then on that symbol expands – if it lands on enough reels, it fills each of those columns from top to bottom.
This shelf suits players who have already tried a few classic slots and know what a payline is. The general workings of free rounds, multipliers and wilds are covered in the special features lesson; here we only look at their book-style versions.
Book slots rarely give you a long, calm ride. The base game is often quiet, and the bigger payouts are concentrated in the free round.
That leads straight to the shelf’s defining trait: volatility.
The Books shelf at a glance
| Feature | On this shelf | Why it matters to you |
|---|---|---|
| Grid and lines | Typically 5×3 with few fixed lines (often 10) | With few lines, each line bet is fairly large, so a single hit is clearly felt |
| Book symbol | Wild and scatter in one; 3 or more trigger the round | One symbol does two jobs – the help screen describes both |
| Expanding symbol | Drawn before the free spins, it fills whole reels | This is where the big payouts come from, not the base game |
| Risk | Studios mostly label these high or very high volatility | Expect long quiet stretches |
| Gamble | Many book slots offer a ‘double or nothing’ after a win | Optional – you can skip it, and with a bonus it counts as a bet |
Two typical titles on this shelf come from two different studios in the lobby.
Book of Kemet is a BGaming game, released on 9 March 2023. According to the studio, it runs on a 5×3 grid with 10 lines, its RTP is 94.94%, it is rated ‘Very high’ for volatility, and the maximum payout reaches ×7,500 your stake. Three or more Books award 10 free spins, and beforehand the game picks a random expanding symbol. Each retrigger adds another expanding symbol, up to 9 in total. A bonus buy is included, but the studio does not publish its price. Going by the lobby, a demo appears to be available.
Lord of the Ocean is a Novomatic classic with an underwater theme. Here the GATE symbol is both wild and scatter, and the free games round also uses a special expanding symbol. The lobby lists a separate ‘Buy Bonus’ version as well. The studio does not publicly state the RTP or the top win, and as a Novomatic title it has no demo – it only runs for real money.
How to pick a book slot and start a round
- Open the Books tab on the slots page and look for the studio name on the tile.
- Read the info panel. Find out which symbol is the book, what the expanding symbol does and whether the round can be retriggered.
- Check RTP and volatility if the studio publishes them. Where there is no data (as with Novomatic), make a note of that too.
- Try the demo if the game offers one. If not, start at the lowest stake.
- Set your stake so that your budget can survive the quiet stretch before the free round.
- Decide in advance whether you will gamble. If not, press ‘Collect’ or ‘Take’ after every win.
- Keep an eye on your history. After a few dozen spins, compare what you staked with what came back.
What is it worth when the symbol opens up?
Worked example with invented values – independent of Dukat.bet:
An invented book slot runs on 10 lines, and your stake is 1 EUR, so 0.10 EUR per line. In the free round, the expanding symbol lands on three reels. The paytable says three of these symbols pay 5 times the line bet. How much does the hit pay without expanding (on one line), and how much once expanded?
Solution. Without expanding, one line pays: 0.10 × 5 = 0.50 EUR. Once expanded, the symbol fills the whole column on all three reels, so it sits on every one of the 10 lines: 10 × 0.10 × 5 = 5 EUR. The same three symbols are worth ten times as much.
Now add the gamble. If you put the 5 EUR on a card-colour guess, you have a 50% chance of 10 EUR and a 50% chance of nothing. The expected value stays at 5 EUR; only the outcome becomes more extreme – gambling does not improve your odds, it simply adds variance.
Book slots with an active bonus
Arriving at the Books shelf with a bonus means, at Dukat.bet, playing on Slots Bonus – 500% up to 3,000 EUR + 15% Cashback. Shared terms let slots count 100% towards wagering, so book slots belong here in principle. Still, check two things.
The first is the stake cap. Under point 2.7, bets above 5 EUR are not allowed by default while you are wagering, and that covers gambling a win as well as a purchased bonus round. A win you have doubled a couple of times can easily push past the limit. The second is the long list of excluded slots, where it is worth looking up your chosen title. The details are in the bonus dictionary.
Four things before you open the book
- You know which symbol is the book and how many you need for the free spins.
- You have checked whether the studio publishes an RTP. Book of Kemet does; Lord of the Ocean does not.
- Your budget can handle a longer quiet stretch. That is what very high volatility means – see the risk levels lesson.
- You have decided whether to skip or use the gamble, and with a bonus you count that stake towards the 5 EUR as well.
Once this shelf feels familiar, move on to the Hold & Win shelf, where reels don’t open up – coins lock into place instead.