Starball Tutorial [Leaf Day]
Introduction
In Starball, four cats from your village (separated into two teams - a red team and a blue team) will each stand around a tree in a play area that is divided into four corners (one for each cat). Cats will "boop" the ball back and forth between their corners. If at any point a cat "drops the ball" by either letting it rest stationary on the ground in their corner or allowing it to bounce out of the play area, the opposing team gains a point and the cat that dropped the ball starts the next round.
The game ends when one of the teams accumulates 3 points.
As a special note: Traditionally, each team shares snacks before the game. These are usually light refreshments or treats, but are necessary to keep them going through a long afternoon of fun!
How to Play
In order to start a new game, you'll need to feed your cats 8 HP worth of adventuring snacks! After doing so, each cat in the game will be dealt three cards from their team's deck.
Each team's deck is composed of two sets of cards mixed together: one set for each cat on the opposing team. On those cards is a 3x3 grid which corresponds to the 3x3 grid in each cat's corner. Grid spaces on the cards can be marked empty (meaning this card can neither defend nor attack that space), yellow (meaning this card can defend that space), or star-marked (meaning this card attacks that space and can also defend it).
Below are all of the grid patterns that can appear on cards. A full deck for a team has one of each grid pattern card for each opponent.

In addition, each cat has two special Boop Cards in their hand! These cards match their current location in the area. That is to say, a cat can always automatically block balls that land on their current space or adjacent to it! (For strategy reasons, try to make sure you are directing the ball outside of an opponent's boop range!)
Once cards are dealt, the cat in the Stars Position (top left, blue team) always plays first. To "boop the ball", each cat plays a card from their hand that will send the ball into an opponent cat's corner. That cat must then play their own card that allows them to block the space that was marked with a star on the previous cat's card. This played card sends the ball along to a new cat's corner, and so on.
Play continues until a cat does not have any cards that allow them to block the ball and continue the chain. When this happens, the ball is considered "dropped."
Rewards
At the end of the game, you will receive x1 Leaf Day item and Leaf Day stamps
according to the following table:
Win 3-0: 6 stamps
Win 3-1: 5 stamps
Win 3-2: 4 stamps
Loss 2-3: 3 stamps
Loss 1-3: 2 stamps
Loss 0-3: 1 stamp
Additionally, if you and your opponent manage to keep a single round going for at least 10 boops, you'll get a bonus stamp (+ an additional bonus stamp for every 5 boops after 10!)