# What Is a Rule Seed? The Number on Every Manual

- Author: Bomb Appétit (https://bombappetit.com)
- Published: 2026-10-20
- Category: Rule seeds
- Canonical: https://bombappetit.com/blog/what-is-a-rule-seed-number-on-every-manual

> What is a rule seed? The number printed at the top of every Bomb Appétit manual. Where you see it, which numbers work and why both sides must share it.
What is a rule seed? In Bomb Appétit it is the number that generates every rule in the manual. It is printed at the top of each manual's first page, it can be any whole number from 1 to 999,999, and the bomb and every copy of the manual must use the same one, or the instructions go wrong.

## Where the rule seed number appears on screen and on paper

The rule seed shows up wherever a bomb or a manual is chosen. The manual names it in its header and its opening paragraph. The setup screens name the manual to open. The missions list names each mission's manual. In an online room, the lobby tells everyone which manual the Experts will use.

Here is where to look, and what to read in each place:

| Place                    | What you see                                                                      | Who reads it              |
| ------------------------ | --------------------------------------------------------------------------------- | ------------------------- |
| Manual header            | The word "manual" and the number, plus "(standard)" on seed 1                     | Every Expert              |
| Manual opening paragraph | "This is manual number" and the seed, with a warning to check the bomb            | Every Expert              |
| Freeplay setup on Play   | The "Manual (rule seed)" field and a button reading "Open manual" with the number | The Defuser               |
| Bomb briefing screen     | "Experts open manual" and the number, as a link                                   | The Defuser               |
| Missions list            | Each mission's details line ends with "manual" and its seed                       | Whoever picks the mission |
| Online room lobby        | "Experts will use manual" and the number                                          | Everyone in the room      |
| Online room, Expert view | The manual for the room's seed, loaded once the bomb is armed                     | Each Expert               |

The header line prints. A paper copy carries the same "manual" number at the top of its first page, so a printed stack can be checked against the bomb just like a screen. The sidebar with the seed box does not print.

The address bar is one more place. A manual's address ends in its number, such as [manual 1](/manual/1) for the standard manual.

## Which numbers can be a rule seed?

Any whole number from 1 to 999,999 works. That is nearly a million different manuals. Seed 1 is the standard manual that most missions use. Every other number in the range produces its own generated manual, and the same number always produces the same one.

A few things are not rule seeds:

- **Zero and negative numbers.** The range starts at 1.
- **Numbers above 999,999.** Seven digits is too many.
- **Numbers with a leading zero in the address.** An address such as `/manual/007` shows a not-found page; use `/manual/7`.
- **Decimals.** The seed boxes round a decimal down to a whole number.

No number in the range is special apart from 1. Seed 1 is stored as data files so it stays put when the game's generators change. The guide on why [standard manual seed 1 never shifts](/blog/standard-manual-seed-1-rules-never-shift) covers that promise and when a group should leave it.

Who chooses the number depends on how you play. In freeplay you pick it. In a mission it is fixed: nineteen missions use seed 1 and the final one uses seed 2026. The comparison of [freeplay rule seeds and mission seeds](/blog/freeplay-rule-seed-vs-mission-seeds) explains what each choice costs.

## Why must the Defuser and every Expert share one rule seed number?

The bomb judges every action by the rules for its own seed. The Experts can only read the rules for the manual in front of them. If the numbers differ, an Expert gives a correct instruction for the wrong rules, the Defuser follows it, and the bomb counts a strike. Nothing on the page warns them.

The danger is that manuals look alike. Every seed has the same modules in the same order with the same layout. Only the content inside the pages changes. An Expert on the wrong seed sees nothing odd until the strikes start.

With several Experts, each one has to match, not just one. If three Experts are on seed 1 and a fourth has an old tab on another seed, that fourth Expert will disagree with the others at some point. That disagreement is a clue, but by then a strike may already have landed.

The fix is a ten-second check before arming: the Defuser reads the number from the setup or briefing screen, and every Expert reads theirs from the manual header. The fuller routine is in the guide to [checking the manual and the bomb share a seed](/blog/games-with-random-rules-rule-seed-manual#checking-the-manual-and-the-bomb-share-a-seed). For the background on seeds and how they generate a manual, read the [games with random rules guide](/blog/games-with-random-rules-rule-seed-manual).

## The rule seed edge case: an empty or zero seed box

An empty or zero seed box never produces a manual for seed 0. What it does instead depends on which box it is. The freeplay field snaps back to 1, the standard manual. The manual sidebar's box simply ignores the Open button. Either way, nobody ends up on a seed they meant to choose.

The freeplay case is the one to watch. If a player clears the "Manual (rule seed)" field or types 0, the field turns it into 1. A player who meant to type a new number but got distracted could arm a seed 1 bomb while the Experts open some other manual. The "Open manual" button beside it always shows the number that will be used, so read it before dealing.

The manual sidebar behaves differently. Its Rule seed box accepts the number you type, and the Open button only moves to a new manual when that number is between 1 and 999,999. An empty box, a zero or a seven-digit number leaves the current manual on screen. The header at the top of the page still names the seed you are actually reading.

To change the number deliberately from the sidebar, follow the steps in [changing the rule seed from the manual sidebar](/blog/how-to-change-the-rule-seed-three-places#can-you-change-the-rule-seed-from-the-manual-sidebar). After any change, read the header again before the timer starts.