Focus Punch is one of the most powerful fighting-type moves that you can find throughout the Sinnoh region. This move has a massive 150 power and is guaranteed to hit (as long as the user doesn’t get hit while they are charging it). It will take some time before you can get your hands on this powerful move. Here is where you can find this TM in Pokémon Brilliant Diamond and Shining Pearl.
Before you can get your hands on this move, you will first need to learn Rock Smash, Strength, and Surf. This means you won’t be able to get this move until you have beaten all of the gym leaders. Once you can use all of these moves outside of battle, go to Oreburgh City and travel west to the Oreburgh Gate cave.
After going inside the cave, take the north path to where the stairs are. You will enter a large room below. Travel south until you find a body of water. Use surf and travel west to the left side of the water. Here you will find a veteran trainer blocking the path to a staircase. Defeat the trainer and head down the stairs. There are two items here. The item to the north behind the boulder contains the move Focus Punch.