Koch method is to do "full speed" Morse code from the beginning, but only learn 1 or 2 letters at a time.

This Javascript page starts with the letters "k" and "m" for Lesson 1. Then, in Lesson 2, you learn "k, m, and r". Etc. etc.

The way the app works is click on the "k" to hear how "k" sounds. Then click on "m" for its sound. Finally, hit the "Start Lesson" button, and the computer will make a random mix of k and m (and extended pauses, which means "space").

You type in "k m k mm mmkkm" or similar into the textarea, and the computer then sees how accurate you were.