His three note books.
The most important item in any labor negotiations are the terms. They dictate what is to be accomplished and how.
camoflosh
it is the most important item in mathematics
A horse.
the most important trading item in china was silk, gunpowder, fireworks, and knowledge/ideas.
The Fountain.
peppercorn, spices
invisible
The amazing and exotic surfboard which can be obtained as an invisible item in sandgem beach. When you give this item to a Pokemon it can learn surf and if you take the item from the Pokemon it immediately and abruptly forgets the hidden machine surf
more invisible, most invisible
Access to water
money