Yoko-Tsuki is the side punch of Karate. Sometimes found in kata, it’s more of an exercise than an actual punch: not only you don’t have any force besides the one of your arm, but actually the shoulders restrain you making the punch weaker than a Choku-Tsuki.
Traditional execution:
Where to use (✅ - Use; ❌ - Don’t use; 🟨 - Last resource):
Video examples: