Charlie, you sure keep us on our mental toes!
The Gemara in Kesubos 111a says that there are six Shavuos:
- Not to go up en masse.
- Not to rebel against the nations.
- The nations should not be too harsh on us.
- Not to reveal the end.
- Not to push the end.
- Not to reveal our secrets.
The Gemara first mentions the first three alone, and then brings the rest in the name of Leivi. People often refer to the ‘Three Shavuos’ because of the facts that it is separated in the Gemara, and that the first three pertain directly to the Galus.
In the Hoshanos, four are mentioned because we are referring to all of the Shavuos that are related to Geula. Two of them, not to reveal our secrets and the one for them not to press us too much, aren’t directly related to the Geula.