| Name | Type | What it does | How long |
|---|---|---|---|
arena.v1.games | Local storage | Your saved games, so you can resume, rename or delete them. If you post a year to the Countermove Index, the game also keeps that year's random key, so the year is posted once. | Until you delete the game or clear site data. Up to 30 games are kept. |
arena.v1.current | Local storage | Which game to reopen when you come back. | As above. |
arena.v1.pins.GAME | Local storage | Up to three numbers you pinned in the data room, shown beside your decision in that game. | Until you clear site data. |
arena.v1.roomSeen | Local storage | Which data room sections you have opened in the current quarter of each game, so the New labels clear once read. Never sent anywhere. | Until you clear site data. The last 20 games are kept. |
cm_accounts | Session storage | Whether accounts are switched on for this site, so the header asks once per tab before showing Sign in. Never sent anywhere. | Until you close the tab. |
arena.v1.teach | Local storage | Teachers only: the classes you created and their private keys, so you can manage the leaderboard. | Until you clear site data. Up to 20 classes. |
arena.v1.match.CODE | Local storage | Team play only: your team's key for a match, and whether the team posted its year to the Countermove Index. | Until you clear site data. |
arena.v1.matches | Local storage | Hosts only: the matches you created and their host keys, so you can run them. | Until you clear site data. Up to 20 matches. |
arena.v1.player | Local storage | A random id for this browser, so you post one result a day to Today's challenge. It is sent with that result. | Until you clear site data. |
arena.v1.progress | Local storage | Your daily streak and personal bests: days played, years played, best grade, best Index alpha and the ids of years you posted. Never sent anywhere. | Until you clear site data. The last 60 days are kept. |
arena.v1.group | Local storage | Only if you add one: your team, school or company, sent with results you post so they count on group boards. | Until you clear it or clear site data. |
arena.v1.tips | Local storage | Whether you hid the desk tips that introduce one tool a quarter in your first game. Never sent anywhere. | Until you clear site data. |
arena-academy-v1 | Local storage | Your Academy progress and best certificate score. | Until you clear site data. |
arena.editionKey.ID | Local storage | Only if you open a private edition link: that edition's access key, sent with requests for its private Index board. | Until you clear site data. |
arena.v1.optimiser | Session storage | Which optimiser answers you paid for in this session, so the Advisor fee is charged once. | Until you close the tab. The last 60 are kept. |
arena.edition | Local storage | Which edition you opened (for example a company's offsite version), so its names and colours stay on. | Until you clear site data or open the standard edition. |
sb-PROJECT-auth-token (may be split into .0, .1) | Cookie (HttpOnly, Secure, SameSite=Lax) | Accounts only: keeps you signed in. Page scripts cannot read it. Removed when you sign out or delete your account. | Up to 30 days; the session itself is refreshed every hour. |
sb-PROJECT-auth-token-code-verifier | Cookie (HttpOnly, Secure, SameSite=Lax) | Accounts only, during “Continue with Google”: the secret half of the PKCE check, so a sign-in code only works in the browser that started it. | Until the sign-in finishes. |
cm_next | Cookie (HttpOnly, Secure, SameSite=Lax) | Accounts only: which Countermove page to return to after signing in. | One hour, or until you sign in. |
cm_in | Cookie (Secure, SameSite=Lax) | Accounts only: holds “1” while you are signed in, so pages know to show your initials. No id, name or email. | Until you sign out, at most 30 days. |
arena.v1.sync | Local storage | Accounts only: whether “Keep my games in my account” is on in this browser, and for which account (a one-way tag, not your id or email). | Until you switch it off, sign in as someone else or clear site data. |
| (none) | Browser-held password | Only on password-protected preview links: your browser remembers the review password you typed (HTTP Basic authentication). Countermove sets no cookie for this. | Until you close the browser or clear saved passwords. |
Managing it
Delete games from the Games menu in Countermove, or clear this site's data in your browser settings. Blocking local storage still lets you play, but games won't be saved between visits.
If this changes
If we ever add a cookie or other storage that isn't strictly necessary, we will ask for your consent first, with a choice as easy to refuse as to accept, and update this page.