Where is the red singpost in Dragon Quest IX?

Answer 1

The red signpost is located on a small island located North of the continent that has Wormwood Creek and Upover on it. I suggest sailing from Alltrades Abbey in between the land masses that have Wormwood Creek and Angel Falls. It's a very small island, and it looks dead. The sign is on the Southern side of the island. Hope this helped.

Answer 2

On an island east of the Bowhole. Read the back of the sign and return to the swords teacher to complete the quest.