Book of Oil by Endorphina: Book symbol and expanding feature guide

Book of Oil is a five-reel, three-row game with ten paylines. Endorphina publishes 96.05% RTP, high volatility and a €0.10–€45 supplier stake range. Three or more Book Scatters trigger ten Free Games with a randomly selected expanding symbol; the feature can retrigger.

The figures describe the provider profile checked on 8 October 2026. They do not prove availability at a New Zealand operator, an NZD limit or the exact RTP configured for an account. Open the loaded help before relying on any number.

Published specification

Field	Provider value
Grid	5×3
Paylines	10
RTP	96.05%
Volatility	High
Bet reference	€0.10–€45
Feature trigger	3+ Book Scatters
Initial Free Games	10
Five-Scatter award	200× base bet

The provider also lists Classic Risk and Bonus Pop. Bonus Pop may be unavailable in some casinos or jurisdictions. Record optional controls separately from the core rules.

Ten-line base evaluation

Ordinary symbols pay on enabled lines across adjacent reels from the left. Only the highest combination on each line is paid. Scatter results can count anywhere and are added to line wins.

The oil tycoon is the top published regular example at 500× base bet for five. The oil machine pays 200× for five. These are paytable examples, not cash values until the live help defines base bet in relation to total stake.

Save the numbered line overlay and a simple result. Note the exact path, symbol count, any Book substitution and displayed credit. A visual row outside an enabled path should not be counted.

Book as Scatter and Wild

The Book performs two jobs. As Scatter, three or more copies start Free Games and five pay 200× base bet. As Wild, it substitutes for regular symbols. One symbol can therefore contribute to an ordinary line and a Scatter count under the game rules.

Do not replace a missing Book with another Wild; the Book itself is the game’s Wild and Scatter. During Free Games it cannot substitute for the specially selected expanding symbol. That restriction prevents the Wild from manufacturing extra copies of the chosen symbol.

For a mixed trigger, record Book positions, Scatter award and every line where a Book substitutes. Reconcile their displayed sum with history before considering Risk.

Ten Free Games and symbol selection

At feature start, one eligible ordinary symbol is selected at random for expansion. Capture the selection screen and the opening counter. The selected symbol remains a feature state, while the Book retains its separate Wild/Scatter identity.

Special symbols expand after regular-symbol payouts. This order matters: first record normal line settlement, then record the additional expanding-symbol evaluation. Do not count the original line twice simply because the symbol later expands.

The feature can be won again. If Books retrigger it, capture the counter before and after the event. The public description confirms retriggering but the current help should determine the exact added-spin treatment.

Adjacent and non-adjacent expanded wins

The selected expanding symbol can pay combinations in adjacent and non-adjacent positions, provided those positions lie on enabled paylines. “Non-adjacent” does not mean every copy anywhere on the screen pays.

Use the line overlay to mark the selected symbol’s coordinates. Compare a qualifying separated arrangement with a visually similar group outside an enabled path. The result highlight should establish why one pays and the other does not.

The Book cannot substitute for the selected symbol during this feature evaluation. When a line includes a Book and two selected icons, use the live result panel rather than assuming the Book completes the expanded combination.

A feature ledger that avoids double counting

Create columns for free-spin number, selected symbol, Book count, regular line credit, expanded coordinates, expanded-symbol credit, retrigger and final spin total. Preserve the order displayed by the game.

At completion, add spin totals and compare them with the feature summary. Then check the parent round in server history. Establish whether the triggering Scatter award sits inside or beside that summary before adding it.

If the interface groups all ten spins under one round ID, save the feature summary plus individual screenshots only for events that need explanation. A concise ledger is more useful than an unlabelled screen recording.

Risk and Bonus Pop

Classic Risk can allow repeated double-or-nothing choices after an eligible win. It is a separate post-settlement wager and should never be used to calculate the underlying ten-line or expanding-symbol result.

Bonus Pop is listed but jurisdiction-dependent. If shown, capture price, entry condition and any changed RTP disclosure. A paid shortcut does not reveal natural trigger frequency and should not be mixed with organically triggered Free Games.

For a baseline audit, decline Risk and leave Bonus Pop off. Verify natural settlement first, then document optional routes as separate transactions.

RTP, volatility and stake scope

The 96.05% RTP is a theoretical long-run setting for the cited provider profile. It cannot predict when three Books land or what ten Free Games return. Verify the active value in the loaded help.

High volatility is Endorphina’s category, not a promise of large wins. A short session can differ sharply from the theoretical return. Do not increase stake because a Book or selected symbol has not appeared recently.

The €0.10–€45 range is in euros. It must not be rewritten as NZD. Record the live currency, minimum total debit, increments and maximum at the operator.

Mobile, demo and access checks

Endorphina describes mobile support and may provide a demo. Demo mode can show the line map and selection sequence but does not prove real-money access or the same certified configuration.

On a phone, verify that all reels, chosen-symbol indicator, counter, stake and history link remain readable. Rotate the device and enlarge text. The feature selection and close controls should not be clipped.

Before paid play, save title, provider, version, RTP, currency, limits, line count, optional-control status, domain and check date. For a dispute, add round ID, trigger grid, selected symbol and final feature summary.

Common interpretation errors

• Treating the Book only as Scatter or only as Wild.
• Letting the Book substitute for the selected expanding symbol.
• Reading non-adjacent as anywhere-pay.
• Counting regular and expanded evaluation twice.
• Adding the five-Book award twice to the feature total.
• Converting euro limits into NZD.
• Claiming New Zealand access from the studio catalogue.

Testing the order of feature settlement

Book of Oil states that ordinary symbols are paid before the selected symbol expands. A useful demo test therefore needs two screenshots from one spin: the first after the normal line highlights and the second after expansion. Label the credited amount visible at each stage. If the interface shows only one final total, keep the two grids but do not manufacture an intermediate value.

This test is most informative when the selected symbol already forms an ordinary line before expansion. The ordinary award should be identifiable first; any later qualifying non-adjacent arrangement belongs to the special evaluation. The same visual icons can participate in both stages only where the current help and result display support it.

Reading a five-Book result

Five Books carry the published 200× base-bet Scatter award. Because the Book is also Wild, the same screen may contain ordinary paylines that use one or more Books as substitutes. Build the settlement from the result list: note the Scatter award once, then each paid line once.

Do not multiply the 200× figure by the number of lines or by the number of Books. It is the stated five-Scatter example. If the complete paytable displays different awards for three and four Books, record those values from the loaded build rather than extrapolating between zero and 200×.

Version-change procedure

When a later check shows another RTP, stake range or feature wording, save the new help screen with date, operator and build identifier. Do not overwrite the provider’s 96.05% profile as though it never existed. Add the newly observed configuration alongside it and state which source governs each claim.

If Bonus Pop appears or disappears, treat that as a deployment observation. Optional-feature availability can change independently of the underlying ten-line rules. The article should be corrected only after the observed control and its terms are captured.

Responsible feature observation

An expanding symbol can create the impression that a near-complete screen is progressing toward a future result. It is not a persistent meter unless the help explicitly describes one. Each paid spin is a new wager, and a previous expansion does not make another more likely.

Use a permitted demo for interface research where possible. In real-money play, set a fixed loss and time limit before beginning. Do not extend a session to obtain a missing screenshot, trigger a retrigger or validate a theory about the selected symbol.

Final assessment

Book of Oil is best audited in stages: ten-line settlement, Book Scatter/Wild treatment, selected-symbol expansion and retriggers. The order prevents one animation from becoming two recorded awards.

The official page supports the 5×3 grid, ten lines, 96.05% RTP, high volatility, ten-spin trigger and expansion rule. Live help remains decisive for the active build and account access.

Official and related sources

• Book of Oil official product page
• Endorphina catalogue guide
• Responsible gambling guide
• Corrections policy

How to verify the version you can actually open

A provider page proves that a title exists and describes the supplier's intended rules. It does not prove that a casino accepts players in New Zealand, that the title is enabled for a particular account, or that the highest published RTP is the version in the lobby. Treat availability, operator eligibility and product configuration as three separate checks.

Start with identity, then configuration

Open the game only through the authenticated casino lobby. The information or help panel should identify Endorphina, the exact title and the active mathematical return. Compare the reel or grid layout, paylines or cluster rules, named features and symbol behaviour with the official product material. Similar artwork or a matching title is not enough when the help file is missing or inconsistent.

When the supplier publishes several RTP values, report all of them as configurations. Do not assume the highest option is deployed. RTP is a theoretical long-run measure across a very large number of rounds; it is not a refund rate for one player and cannot predict the next result. Volatility is different: it describes how unevenly results are distributed on the provider's scale.

Read stake controls as money, not interface decoration

Provider sheets often quote a reference range in euros. That range does not establish New Zealand-dollar support or the limits in a specific account. Before a paid round, identify the total amount that will leave the balance. If the interface separates denomination, coins and lines, verify the combined total. If Extra Bet is active, calculate its full cost before pressing spin.

Feature-buy prices are multiples of the current bet, not promised returns. A 100x purchase at a $1 stake costs $100; at a $2 stake it costs $200. Availability can vary by market and some mathematical configurations may not support the control. If the live help does not explain the price, delivered feature and active RTP, leave the option unused.

Keep simulation figures in their proper scope

A game sheet may publish a maximum result observed in a large simulation. That is not automatically the contractual maximum payout and never describes a likely session. Preserve the provider's wording, sample size and configuration. Check the live rules for a binding cap and the operator terms for any separate payout limit. Do not turn an extreme result into a promotional headline.

Audit a disputed round

If an animation freezes or a connection drops, do not repeat the wager immediately. Reopen the game through the authenticated lobby and inspect round history. Record the time, total stake, balance movement and round identifier. The result can be settled by the gaming system even when the device never displays the final animation. Send evidence through verified operator support; never disclose a password, recovery phrase or one-time code.

Read the paytable as a calculation document

The paytable should explain what creates a win, which symbols substitute, where special symbols can land and how multiple awards combine. For line games, confirm direction and active paylines. For cluster games, confirm adjacency, minimum group size and the order of collection. For respins, identify what remains locked, what resets the counter and what ends the feature. A graphic effect can illustrate those rules but cannot replace them.

Separate addition from multiplication. Several prize values may be added before a multiplier applies, while reel-specific multipliers can sometimes multiply together only when each reel participates in the same win. Reconstruct one low-stake result from game history. If the arithmetic cannot be matched to the help file, stop and ask the operator rather than guessing.

Do not confuse hit frequency with a profitable round

Provider sheets can publish hit frequency or category probabilities. A hit simply means a round returned a qualifying amount; it can be smaller than the stake. “Big”, “Mega” or “Epic” thresholds are provider reporting categories, not promises. They are useful for comparing mathematical versions only when definitions and samples are the same.

Random outcomes do not become due after a long gap. A feature that appeared repeatedly in a demo or marketing clip has no obligation to repeat in a funded session. Previous rounds do not create a debt from the next random result.

Confirm market and device behaviour independently

A title can exist in the supplier catalogue while an operator disables it for a territory, currency, device or bonus. Language localisation is not evidence of legal availability. Confirm the operator's identity, accepted countries and current lobby separately from the provider review.

On mobile, verify that balance, total bet, feature state and help remain visible without overlap. On desktop, check that browser zoom does not hide a purchase control or change the apparent denomination. Mathematical configuration should not change merely because the screen changes; if the help shows another RTP, treat it as a different deployment and record it.

Keep a compact evidence record

For any fact used in a review, save the title, provider, official URL, document date when available, access date and exact territorial scope. For a live session, add the operator domain, Game ID, RTP, currency and a non-sensitive screenshot of the help panel. This makes later corrections possible when a supplier updates a sheet or an operator changes configuration.

Missing information should remain missing. Do not estimate an RTP from results, convert a euro reference range into an operator's NZD limit, or treat another casino's configuration as evidence. A transparent “not confirmed” is more useful than a precise-looking number without the correct source.

Use limits that survive the feature design

Collection meters, expanding grids, sticky symbols and near misses can make a session feel unfinished. Unless the rules explicitly preserve progress, the visible state has no value after the round or feature ends. Set a money limit and time limit before launch, count feature buys immediately, and stop at the limit even when a meter appears close to an upgrade.

No random game is an income plan. Do not borrow, use essential funds or raise the stake to recover a loss. If play stops feeling recreational, use timeout, deposit-limit or self-exclusion tools and consult the site's responsible gambling guide.