Walkthrough: Lost Coin Official

lost_coin
First, accept the quest in the menu.
Start at the village near the hospital.
On the sidewalk, face North and ride to the ocean.
Once in the ocean, face West and sail to the boundary.
Continue sailing West to the western ocean.
The item "silver_coin" is here.
It is a huge area; position yourself in the bottom-left corner of the map facing West, then turn North-West and sail across the ocean diagonally. Alternatively, you can sweep in stripes 25 tiles wide heading West.