How to Get Hidden Power in Emeraldby Shea LavertyUpdated September 22, 2017
In the “Pokemon” games, the move Hidden Power is something of an oddity. Hidden Power doesn't work the same way with any two individual Pokemon. Its attack power and elemental damage-type vary from one Pokemon to the next, based on calculations made using their statistics and growth values. In "Pokemon Emerald Version," you can obtain TM10, the Technical Machine or TM that teaches Hidden Power to a Pokemon.
Receiving TM10 (Hidden Power)
Travel to Fortree City and look for a house northwest of Fortree Gym with an old woman inside.
Talk to the old woman. She will challenge you to a guessing game and you must successfully guess which of her hands is hiding a coin.
Play the old woman's guessing game and guess which hand is hiding the coin at least three times. This may take several tries, but you'll eventually succeed. The old woman will reward you with TM10, Hidden Power.
Buying TM10 (Hidden Power)
Travel to Slateport City and head for the open-air market in the southwestern part of the town.
Visit the stall on the middle right side and find the TM Shop shopkeeper.
Purchase TM10 (Hidden Power) from the shopkeeper for about 3000P.
TMs in Emerald are single-use. This means that when you select a Pokemon to use it on, it will be gone afterward.
You won't be able to buy TM10 from the shopkeeper until you have found TM43 (Secret Power) on Route 111.
Any Pokemon in the game can learn Hidden Power, so TM10 can be used on any Pokemon.