Buying and selling.
Order direction always states exactly what you give and what you receive.
The story in brief
Buying and selling.
Buy and Sell are two perspectives on one exchange, never two unrelated transfers.
The useful context
3 key points
Buying
A Buy order reserves the quoted balance required for its quantity and fee. Accepting a Sell order purchases its available quantity directly.
Why this mattersSelling
A Sell order reserves the eligible asset. Items may fill partially, while a transferable Character always moves as one indivisible entity.
Why this mattersOwnership and delivery
A completed exchange updates both sides atomically and records an internal receipt. A game client cannot grant itself an asset or alter a balance.
Why this mattersMARKET
Two directions, one settlement rule.
The Market keeps asset identity, quoted value and resulting ownership visible throughout every Buy and Sell path.