The in-game text doesn't tell you much, so here are the actual rules: who can enter, how many matches you get, what scores, what the four Airdrop Items do, and the mistakes that cost you a match.
Your score is counted in Blizzard Points, and the Help Center names two ways to earn them:
The Help Center gives no point values for either, and no reward table. Check the in-game event screen for current numbers. One related rule: Brawl Emblems are not recycled after the event ends.
Starting 1 minute and 30 seconds after a battle begins, chests with random items are airdropped into the center region of the battlefield every 2 minutes. You collect them by sending a special loot squad, and you can only have 1 loot squad out collecting Airdrop chests at a time. Each chest holds one of four random items, and there is no limit to how many Airdrop Items you can obtain.
| Item | Effect (per the Help Center) |
|---|---|
| Smoke Bomb | Makes your Town invisible for 20 seconds, so other Governors can't select or attack it. Deploying any squad removes the invisibility. |
| Healing Elixir | Heals 30% of the severely injured soldiers in your Infirmary, up to 500,000. |
| Ice Bomb | Stops an enemy Governor's Town from deploying any squads for 10 seconds. |
| Rocket Bomb | Severely injures 30,000 soldiers of an enemy Governor's Town or garrisoned building. You get 1 on entering the battlefield, then recover 1 every 2 minutes. |
Teleporting still works after your Town is hit by an Ice Bomb, and also after you use a Smoke Bomb.
There are two ways out, and a confirmation pop-up appears before either. Return to Town temporarily lets you rejoin. Quit the event completely and you can only take part in the next cycle of the event. If you can't re-enter, you almost certainly chose the second one.
You can't open the Alliance interface while you're on the battlefield. To leave your alliance, return to your Town first. Be aware that you can still be removed from your alliance mid-battle.
Cancelling matchmaking has no cooldown and no penalty. The penalty applies when matchmaking succeeds but you don't get ready during the Preparation Phase. Repeat it and matchmaking becomes temporarily unavailable to you. The Help Center doesn't give the length of that lockout.
The Help Center says you have a chance to be matched with players from all generations. It states no numeric generation cap, so don't assume one.
Bonuses and items that enhance battle stats are valid. Counter-recon only applies to castles, not to garrisoned buildings. These bonuses are invalid in Blizzard Brawl: Castle Battle titles, Kingdom of Power titles, King skills, High King skills, Tyrant titles, Alliance Territories, Pet Gathering skills, Town Shields and Gathering Speed Boost items.
If the event runs in your old Kingdom but not the new one, unclaimed match rewards arrive by mail. If it runs in both, your remaining attempts and match rewards carry over. If it only runs in the new Kingdom, you can take part after the move.
This section is KingshotPro's own inference from the rules above, not an official ruling.
Which heroes lead your marches is a separate question, and the official rules don't rank them. See the hero tier list and the hero database. For the troops you bring, the troop tiers guide explains the tiers.
6 matches in each season. An attempt is only used when matchmaking succeeds and you enter the battlefield.
Town Center Lv. 25 or higher, at least 10 Governors in the battle, and a Kingdom that has existed long enough. The Help Center says to check the in-game event page for how many days.
From Strategic Supply Chests and Airdrop Items. No point values are published, so check the in-game event screen.
If you chose "return to Town temporarily", yes. If you quit the event completely, you can only take part in the next cycle.
No. The penalty is for succeeding at matchmaking and then not getting ready during the Preparation Phase; repeated failures make matchmaking temporarily unavailable.