Machamp is one of the rarest and strongest Pokemon found in the Generation I games, Red and Blue.
Machamp can only be obtained by receiving a Machoke through trade. The trade is what evolves the Fighting-type Pokemon. That is how its true potential is unlocked.
In Kanto, Fighting-type Pokemon were incredibly powerful and unique. Since it was the first region trainers could ever explore, there was a lot to learn about each creature. Machamp was certainly underused, but extremely useful.
Note: This article is subjective and reflects the opinion of the writer.
The best moveset for Machamp in Pokemon Red and Blue
Machamp can learn Body Slam via TM. In Generation 1, it cannot Paralyze Normal-type Pokemon, but it still does incredible damage. Any other type has a 30% chance of being Paralyzed whenever Body Slam connects. Machamp has an amazing Attack stat, making this move well worth it.
Earthquake is one of the most devastating moves ever introduced in Pokemon. It has 100 Power and 100% Accuracy. It also does Physical damage instead of Special. This gives Machamp some incredible coverage, as the only Pokemon truly unaffected by Earthquake are Flying-types. Machamp shouldn't be in battle against a Flying-type in the first place.
Rock Slide is for those moments when Machamp happens to be across from a Flying-type Pokemon. There is no flinching in Pokemon Red and Blue, but Rock Slide still does decent Physical damage. This will give Machamp an advantage against Flying, Fire, and Bug, while it will already have an advantage against Ice-types.
This is the sole Fighting-type move Machamp will know and it is a doozy. Submission gives Machamp a STAB move, along with being a Physical attack. It does recoil Machamp and deliver damage to it, but it is worth it. There are some incredibly strong Rock, ice, and Normal-types in Red and Blue. Submission will put them down with ease.