Step 1: Recall the Dandi March:
On 12 March 1930, Gandhi marched from Sabarmati Ashram to Dandi (about 385 km) to break the salt law by making salt from seawater.
Step 2: Place it in the correct movement:
This salt satyagraha formally launched the Civil Disobedience Movement (1930-34).
Final Answer:
\[ \boxed{\text{Civil Disobedience Movement}} \]