Bruncheon

Bruncheon is a trickjump that allows access to the main area of the Luncheon Kingdom before it is unlocked normally, by emerging from the Warp Painting and jumping to the mainland below. When the trick is performed on a file where the Luncheon Kingdom has not been unlocked, the kingdom is in a state where the Odyssey is unloaded, meaning the player is unable to progress past the Luncheon Kingdom. Additionally, certain other elements within the kingdom are not present, such as the slab of meat at the top of the Meat Plateau.

Execution

Version 1.0.0

On version 1.0.0, the game will not attempt to place Mario in a bubble when jumping off the island. There are two ways to execute Bruncheon on version 1.0.0:

Single-player method

The only way to complete the Bruncheon jump without the use of tricks exclusive to two-player mode is by precisely jumping so that Mario barely lands on top of the lava at the edge of the kingdom mainland. This trickjump is quite difficult, so very precise movement is needed. The process is as follows:

Stand near the edge of the platform and, optionally, use first-person camera mode to angle Mario properly.
Roll cancel as close to the edge as possible to retain the most speed, and perform a 45-degree vector throughout the duration of the fall.
When Mario is roughly level with the ground, throw Cappy and dive onto him to bounce.
Perform a homing throw and cap return spin for extra distance.
Cap throw and dive onto the lava. If done correctly, Mario will bounce upwards from the lava damage rather than hitting the side, allowing him to be guided onto the Moon Rock platform after one or two bounces.

Some players opt to use a triple throw setup, in which they leave Cappy behind for a long period of time after performing the roll cancel off of the painting island. This must be timed perfectly so that Cappy returns to Mario just as Mario needs to perform the cap bounce, but it has the added benefit of the homing throw becoming a triple throw.

This is also the only way to complete the Bruncheon jump without capturing anything, making it the only variant of Bruncheon that is useful for World Peace Minimum Captures.

Two-player method

Reaching the Luncheon Kingdom mainland early can be performed in a much easier manner using two-player mode. Instead of Mario fully reaching the mainland, Cappy simply needs to touch the Lava Bubble near the small island with the Moon Rock, causing Mario to capture it.

Later versions

Bruncheon is much more difficult on versions 1.0.1 and onward, since normally a bubble will place the player back on the island upon jumping off. However, if the player emerges from the Warp Painting and lands on top of the painting before touching any other ground, the bubble's safe spot will not be set and the bubble will not activate. However, this means the trickjump must be done from the top of the painting rather than the edge of the island closest to the mainland; otherwise, the safe spot will be placed. The only way to do this is using two-player mode. The process is as follows:

Stand at the edge of the painting closest to the mainland (before touching any other solid ground).
Throw Cappy twice to set up a triple throw that will be used later.
Spinpound and roll from the corner of the painting, and vault by pressing A or B on Cappy's controller (making sure to only touch ground that is covered by the painting).
Perform a 45-degree vector throughout the duration of the fall.
Around halfway through the fall, release Cappy by pressing X or Y on Cappy's controller.
When Mario is almost roughly level with the ground, return Cappy by pressing X or Y on Cappy's controller.
The moment Cappy comes back, perform a homing cap throw and cap return spin. This should be a triple throw if it was set up properly.
Perform a cap throw and bounce.
Move Cappy onto the Lava Bubble to capture it.

Because this method involves capturing the Lava Bubble, it is not useful for World Peace Minimum Captures. Bruncheon must be performed on version 1.0.0 to save a capture.

Behavior

In the Bruncheon state of the kingdom, the Odyssey is unloaded, meaning that Mario cannot progress past the Luncheon Kingdom until reaching it through normal means. Additionally, Spewart is not present, meaning the story cannot be progressed normally. However, the Multi Moon above the stew pot is present, despite not actually being present initially in regular first-visit Luncheon Kingdom. This Multi Moon can be collected using Meat Skip.

After the Multi Moon is collected, the moon from the Spewart boss fight (The Broodals Are After Some Cookin) as well as the Under the Cheese Rocks moon appear out in the open, without the need to defeat Spewart or pull the lever that is normally used to break the cage surrounding Under the Cheese Rocks. The story can also be progressed further by collecting the story moon in the Cascading Magma level and then continuing to climb up to the Cookatiel fight. If Cookatiel is defeated, the game will softlock after Mario is transported back to where the Odyssey would normally be located.

Theorized speedrun route

Despite the game preventing progression to the later kingdoms from this early state of the Luncheon Kingdom, some players have theorized a route for the Any% speedrun category that entails using the Bruncheon state to collect moons in Luncheon, then going back through the painting to continue the game as normal.

The proposed route is as follows:

Play through the game normally up until the end of the Sand Kingdom, but select Wooded Kingdom before Lake Kingdom. (This ensures the painting to the Luncheon Kingdom is faster to reach.)
Complete the Wooded Kingdom normally, but collect a Life-Up Heart from a brick block inside the Sky Garden Tower.
Upon reaching the Lake Kingdom, collect the first moon as normal, then enter the Warp Painting to the Luncheon Kingdom.
Collect the moon on the painting island, and perform the Bruncheon jump to reach the mainland.
Capture the nearby Lava Bubble and use it to collect the moon on Salt-Pile Isle, then enter the Fork Flickin' level and collect both moons. Afterward, head over and collect the Atop the Jutting Crag moon.
Capture the Goomba below and use it to make a stack of two. Bring the stack over to the rainbow-colored mountain ridge and leave them in that area temporarily.
As Mario, collect the moon atop the pillar, the moon from the golden turnip, and the moon inside the crate.
Recapture the Goomba stack and use it to perform Meat Skip, using the Life-Up Heart that was collected earlier.
After being taken back to the Odyssey, collect the nearby Timer Challenge moon, warp back up to the painting island, and return to the Lake Kingdom.
Collect the remaining seven moons in the Lake Kingdom, and continue to progress through the game as normal until reaching the Luncheon Kingdom.
Upon returning to the Luncheon Kingdom, collect the salt moon on top of the large wall, followed by the moon from the two torches. Next, collect the alcove moon and head up to the Spewart arena.
Since Meat Skip was performed earlier and the Multi Moon in the stew pot was collected, Spewart will not be present. Collect the Timer Challenge moon, followed by the moon that would normally be awarded after defeating Spewart.
Enter the Magma Swamp sub-area, collect the moon near the entrance, and then warp back to the Odyssey. Continue to progress through the game as normal.

Other uses

The Bruncheon trick can also be used for various other purposes:

World Peace Minimum Captures: Using the Bruncheon trick to access the mainland early and perform Meat Skip only uses a single capture optimally (the Goomba), while achieving World Peace normally requires a Hammer Bro capture and the Meat capture. However, the more challenging single-player version of the trick must be used here, since the two-player variant relies on the capture of a Lava Bubble.
Star%: Using the Bruncheon jump to access Luncheon early, and then using the Warp Painting to the Mushroom Kingdom within Luncheon is the most optimal way to collect a star on a new save file.