Starball can be a bit overwhelming at the start, but once broken down, it's a pretty simple and easy to grasp minigame.

Starball?
Starball is a Leaf Day exclusive minigame where four randomly chosen cats (from your active or traveling slots) play a game of four square. Cats are divided into two teams of two on opposite sides of the tree.

Pick a cat, feed them 8HP worth of snacks, and begin!

How to Play
This is what the game area looks like:

Cats in order from left to right, top to bottom, are: Aurelian, Reaper, Pike, and Sage.

For this example, we are playing as Aurelian.

The Stars Corner (purple) always serves the very first move at the start of the game, regardless of if you picked to play as that cat or not.

Every cat has a set of cards in there hand, shown below the game area:


You have 3 normal play cards and 2 boop cards.

The 3 normal play cards get expelled on use. You draw a new normal play card on use.

The 2 boop cards change depending on your position within your square. You will always have 2 boop cards, one for each opponent.

The cards are color-coded per opponent and also have a marker in the top-right corner on which opponent's square the ball will go to on usage.

So many squares!
Each card has a 3x3 grid with some colored tiles.

The yellow tile with the star is where the ball will land in the opponent's square. If I played my Throw card from above, for example, it would land here:


The adjacent yellow tiles are defended tiles. You must play a card that has the tile marked in yellow in order to keep the other team from scoring.

The grey tiles are undefended squares. If an opponent tosses the ball into a grey tile, you cannot use that card to defend your square.

Looking at my hand above, you'll see that an opponent won't be able to score a point on me unless they tossed the ball into the very bottom-right and top-right corners of my square.

Turns in action
We've used the Throw card, so here is how the first turn looks:


For his turn, Reaper has thrown the ball back at me. Here's the board:


And here's my hand:


Nudge, the new card drawn after using Throw, is greyed out and cannot be used as it does not have a yellow tile where the ball is. Every other card is fair game.

The Boop Zone
To win, you will ideally want to avoid The Boop Zone. The Boop Zone is all adjacent tiles to the cat's current position. The Boop cards allow you to defend all adjacent tiles no matter your position, so you know your opponents always have those tiles defended (and your opponents know that about you!).

Here's an illustrated Boop Zone:

The yellow checks indicate all of the areas Sage absolutely has defended from where they're standing. In order to score a point on Sage, we need to hit the ball in the following tiles:


Of course, just hitting those tiles won't mean a point is secured. Sage may have a normal play card that defends one of those tiles, but at least we know they can't use a Boop card!

Strategy?
Playing for glory and high scores? Try your best to avoid your opponents' Boop Zone, and do your best to position yourself to always have as many tiles defended as possible.

Playing for stamps? You may find it more efficient to try and collect the bonus stamps from high boop chains. Do your best to continually hit into your opponents' Boop Zone, but do note your opponents won't try and cooperate for many stamps!

Happy second Leaf Day! I know the mechanics of Starball can be a bit confusing for people so I wanted to bring this up to make it visible again

this is helpful! i was wondering if there was much strategy involved in starball since it appeared to be mostly rng, and glad to see that its not something i'm just terrible at LMAO thank u for taking the time ..

Thanks a bunch! I looked at the tutorial but didn't really understand it The visuals really help!

YAY this is perfect.. I was also staring at the tutorial wondering what I was missing. I felt like I got the hang of it alone but wasn't sure lol... Looks like I accidentally ended up figuring it out alright but it's nice to have confirmation

This helped so much! Thank you :D

I did have one remaining question though: is there anything that determines where on the board a cat moves to after playing a card? Or is it random? I haven't been able to notice a pattern while playing, but I haven't been taking an extensive survey either.

@YourLocalGrubdog
The cat moves to where the ball is! So if you choose a card to play while the ball is in the top-left tile, after playing a card your cat will move to the top-left tile.

Ah okay! Thank you! :D