// CHAPTER 04
Chapter 4 — Chiffres
The digits 0 to 9. Five symbols each, a clean pattern — learned in under ten minutes.
The 10 signs of this chapter
10 signs to learn in this chapter. Click a tile for the dedicated reference page.
What you learn
Chapter 4 handles all ten digits at once. Their regular pattern (5 → five dots, 0 → five dashes, smooth transition) speeds learning. Essential for RST reports (599), frequencies (7045), and amateur callsigns (F4, F5, F6…).
Mission Morse lessons
Each chapter has two lessons: "listening" (8 audio questions) and "rhythm tap" (6 tapping questions). Lessons chain in Mission Morse once you sign up.