Near Boney Tunnel

Send a lumberjack to destroy the stump. Onii Rings will become vulnerable.

Defeat the Onii Rings and the two pot-throwing Oniis on the ridge to your right. One drops Art Piece 31, "Uncle Frank" by Yukina.

Start digging open the hole. Regular Oniis and club-wielding Oniis will appear. Use hunters to defeat club-wielding Oniis from a distance, or send soldiers if they are stunned.

Continue digging to find a giant treasure.

Defeat the two Oniis overlooking the rock barrier to the north.

Smash through the rock barrier.

Defeat a club-wielding Onii and a pot-throwing Onii on the ridge.

Break through the wooden barrier.

Move ahead and check the map; you are between the Ripe Kingdom and the Kingdom of the Jolly. Find Wonder Spot #5: Forest Cafeteria, west of your entry point.

At the north end of the open area, defeat a Triple Question Mark Pot Onii that spawns enemies like Moonflowers and Rodeo Cows.

Watch out for the two Lotus Root Oniis on the ridges overlooking the giant rock to the north. Shoot them down quickly.

Head to the hammer sign and have your carpenter build the Jump Cannon.

Attempt to smash the lone rock in the open area to reveal an Onii metal. Avoid it and concentrate on digging open the hole.

Find an expensive money chest down there.

Return to your castle to cash in your treasures: 3,000,000 Bol from the precious treasures and 2,000,000 Bol from the money chest. This allows you to build the Furniture Factory in the Stone City.

With the Jump Cannon built between the Ripe Kingdom and the Kingdom of the Jolly, you can invade either country at will.