Real screenshot from our demo test, 1 Nov 2026
BGamingReleased 8 Jul 2020
Book of Cats Demo & review
A six-reel book slot where one open cell on the last reel can extend a winning line in the base game and picks the expanding symbol for free spins.
Written by Hampus GravePublished 2 Nov 2026
Play money · no sign-up · no deposit
- RTP
- 96.99%
- Volatility
- Very high
- Max win
- 8,202x
- Grid
- 6x3 (reel 6 locked except one cell in the base game)
Play Book of Cats for real at YEET
FluxPlays verdict
Our verdict
For spinning, yes. For buying, no. The open cell on reel 6 gives base spins a second way to grow a line, and BGaming puts free spins at one in 140 spins, so the round can come without paying for it. The buy carries a lower RTP than spinning. The drawback is the draw: a low expanding symbol, like the Q our bought round got, keeps a round small.
Who it suits
Play this if…
- Book-slot players: the expanding symbol pays on all lines, even across gaps, with a sixth reel to cover
- Bonus chasers: three Golden Books anywhere start the round, and retriggers have no limit
- Learners: the open cell on reel 6 shows both of the game's ideas at work in full view
Skip this if…
- Bonus buyers: the buy has a lower RTP than the base game and cannot change the draw
- Low-volatility fans: BGaming rates it Very high, and a low draw can sink a round
- You came for the Megaways version: this is the original 10-line game
Where to play Book of Cats
Book of Cats is available at these casinos we have tested and reviewed. How we test casinos
YEET
18+ · T&Cs apply
SafeCasino
FluxPlays score 7.5
Skrill withdrawal paid out in 18 hours in our test
400% up to €4,000 + 1,200 free spins
- 40x wagering
- min deposit €10
- 30 days
400% welcome package up to 4,000 over four deposits, each 100% up to 1,000 plus 300 free spins. 40x wagering on bonus and free spin winnings. Minimum 10 to activate, 200 for the full 300 spins. 30 day validity. Free spins run on Pragmatic Play games.
18+ · T&Cs apply · Offer checked 7 Oct 2026
Betlabel
FluxPlays score 7.0
E-wallet payout inside 24 hours in our test
200% up to €1,500 + 150 free spins
- 35x wagering
- min deposit €10
- 7 days
200% welcome package up to 1,500 plus 150 free spins over four deposits: 100% up to 300 + 30 FS, 50% up to 350 + 35 FS, 25% up to 400 + 40 FS, 25% up to 450 + 45 FS. 35x wagering, 7 day window. Minimum 10 first deposit, 15 thereafter. Crypto deposits are not bonus eligible.
18+ · T&Cs apply · Offer checked 7 Oct 2026
These are affiliate links: we earn a commission if you sign up through them. It never changes our scores. Affiliate disclosure
Book of Cats: Full Review
In Book of Cats, one open cell on the sixth reel does two jobs: in the base game it can stretch a winning line onto a sixth reel, and when free spins start it decides which symbol expands. BGaming released this original 10-line version in July 2020, and the Megaways version is a separate game. It suits book-slot players who would rather spin than buy, since the buy carries the lower RTP.
Book of Cats game information
- Provider
- BGaming
- Release date
- 8 July 2020
- Grid
- 6 x 3 (reel 6 locked except one cell in the base game) (reels x rows)
- How it pays
- 10 paylines
- RTP
- 96.99% (base game) (casinos may also run 96.83% (Buy Free Spins))
- Volatility
- Very high
- Max win
- 8,202x the bet
- Bet range
- $0.10 to $10 (10 lines at $0.01 to $1.00)
- Bonus buy
- Buy Free Spins 97x
- Hit frequency
- 1 in 2.78 spins
- Free spins frequency
- 1 in 140
The base game before our first spin: the sixth reel is shuttered except for one cell. FluxPlays demo test, 1 November 2026.
How Book of Cats works
Ten fixed lines pay from the leftmost reel across adjacent reels, on a grid of six reels and three rows. In the base game the sixth reel is locked except for one cell. When that cell shows the symbol of a winning line, it expands to fill the whole sixth reel and adds to the win, so a five-of-a-kind can become six.
The Golden Book is both wild and scatter. Pays below are at a $1 total bet, ten lines of $0.10:
| Symbol | 6 | 5 | 4 | 3 | 2 |
|---|---|---|---|---|---|
| Cleopatra | $750 | $250 | $50 | $5 | $0.50 |
| Green cat | $250 | $100 | $20 | $2 | $0.20 |
| Cat mask, ankh | $100 | $37.50 | $5 | $1.50 | $0.20 |
| A, K | $37.50 | $7.50 | $2 | $0.30 | |
| Q, J, 10 | $25 | $5 | $1.20 | $0.30 | |
| Golden Book, anywhere | $400 | $200 | $20 | $2 |
After a base-game win you can collect, or gamble it on the colour of a card to double it, or on the suit to quadruple it.
The paytable in line-bet multiples: the Golden Book substitutes for every symbol and triggers 10 free spins. FluxPlays demo test, 1 November 2026.
Free spins: how they trigger and what expands
Three or more Golden Books anywhere award 10 free spins and pay their scatter win. Whatever symbol sits in the open cell on reel 6 as the round starts becomes the expanding symbol, and it can never be the Golden Book. For the free spins the sixth reel unlocks fully, and retriggers have no limit.
After the normal line wins on each spin, the expanding symbol fills every reel it appears on and pays on all ten lines, even across reels that are not next to each other. So the draw sets the ceiling of the round. By the same table, a Q filling all six reels pays $25 on each line. Cleopatra in the same position pays $750 a line.
The Golden Book opening at the start of our bought round, before the expanding symbol was shown. FluxPlays demo test, 1 November 2026.
Our bought round drew the Q, one of the lowest symbols. Two of its ten spins paid $12.00 each, and the round came to $35.90 with the scatter pay from the trigger.
The end screen of our bought round: 33.90 from the spins, before the 2.00 scatter pay is added. FluxPlays demo test, 1 November 2026.
Can you buy the bonus?
Yes, for 97x the bet, and the free spins start on the next spin. The buy's RTP is 96.83%, a little below the base game's, so on paper spinning is the better deal.
Back in the base game after the buy: the round settled at 35.90 with the scatter pay included. FluxPlays demo test, 1 November 2026.
RTP, volatility and max win
The base game returns 96.99%, the version in the demo and on BGaming's game page. Casinos can run lower settings, and some listings quote lower figures. BGaming labels the volatility Very high.
One review site gives 10,000x as the cap, but the game's own intro and BGaming's page both put it at 8,202x the bet. BGaming also publishes a hit rate of 1 in 2.78.
Our Book of Cats demo test
FluxPlays demo test
1 November 2026, demo running 96.99% RTP
Base game spins
100
at $1 per spin
Staked
$100
Paid back
$186.60
186.6% of stake, +$86.60
Winning spins
35 of 100
35% of spins paid something
Biggest win
$102 (102x)
base game: $100.00 on one line through the open cell on reel 6 plus $2.00 on another; next best $37.50 (spin 41, six of a kind)
Free spins triggered
0
natural triggers in the session
Bonus buys tested
Buy Free Spins (97x)
three Golden Books paid $2.00 and gave 10 free spins; the expanding symbol was Q; no retrigger
$97 in
$35.90 back
0.37x its price
35.9x the $1 bet
Played on BGaming's public fun-mode client (build 1.0.0) on 1 November 2026, in FUN credits read as dollars, from a 1,000.00 balance. The demo opened at 0.10 and was raised to 1.00 (10 lines at 0.10) for every round. Quick spin was on, every win was collected and the gamble was never played. A first attempt was stopped part-way by a pause in testing; this card covers the fresh restart only. Every round was checked against the game server, and the session ends at 1,025.50 on the server and on screen: 197.00 spent over 101 paid rounds, 222.50 returned.
Line wins in the base game carried our session, and the sixth reel helped. Spin 9 paid $102.00, most of it from one line that ran through the open cell on reel 6. Spin 41 added six of a kind on another line.
Golden Books turned up 36 times but never three at once, so free spins came only from the buy, and its low draw kept the round small. Over a hundred spins and one buy, luck outweighs the return by far, so none of this is an RTP reading. No high expanding symbol, retrigger or gamble round came up, so for those we rely on the help pages.
Is Book of Cats worth playing?
Yes, if you would rather spin than buy. The open cell on reel 6 gives ordinary base spins a second way to grow a line, and the free spins work like the classic books with a sixth reel to fill. Buying the round costs a little return on paper, and it does nothing to improve the draw.
Pick Book of Dead for the classic 5x3 book at High volatility, with no buy to weigh up. Choose Book of Cats for the extra reel in both the base game and the free spins, if Very high volatility suits you.
In the demo, watch the open cell on every base-game win. When it matches the line, the sixth reel fills, and that same cell is the one that chooses your free spins symbol.
Frequently Asked Questions
How does the sixth reel work in Book of Cats?+
In the base game only one cell of reel 6 is open. If it shows the symbol of a winning line, it expands to fill the reel and adds to the win. When free spins start, the symbol in that cell becomes the expanding symbol, and the whole reel unlocks for the round.
How do you trigger free spins in Book of Cats, and which symbol expands?+
Three or more Golden Books anywhere give 10 free spins, and retriggers have no limit. The expanding symbol is whatever sits in the open cell on reel 6 as the round starts, never the Golden Book. A high symbol there makes a big round possible. Ours, bought, drew a Q.
Can you buy the bonus in Book of Cats, and what does it cost?+
Yes, for 97x the bet, and the free spins start on the next spin. The buy carries a 96.83% RTP against 96.99% for the base game, so it costs a little return on paper, and it cannot influence which symbol expands.
What is the max win in Book of Cats, and how is it reached?+
It is 8,202x the bet, according to the game and BGaming. The route is the expanding symbol: a Cleopatra filling all six reels in free spins pays 7,500x the bet on its own, close to the cap. Our own bought round drew a low symbol and stayed far below that.
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