Masterpiece Plank

The Masterpiece Plank is a treasure in. It is actually a copy of Famicom Mukashibanashi: Shin Onigashima, the Game Boy Advance version of  originally released for the Famicom Disk System.

Collecting the treasure
The Masterpiece Plank is found on a high ledge in the Sightless Passage, on the southernmost point of the sublevel. Only Yellow Pikmin can reach it, but having Oatchi rush against the wall will knock it down. Along the way will be fire geysers and Water Dumples, both of which are recommended to take out before taking the treasure back.

Trivia

 * If viewed in the Newly Nostalgic Series's Treasure Catalog entry, it will be inside the Micromanagement Station. It will be showing the title screen for Shin Onigashima.