When I play a 1v1 match against Zerg as Protoss, I'm happy. So far (in about 5 matches), I found the following strategy undefeatable:

1. Quickly build a Forge (before Gateway), then 2-3 canons at your doorstep. If you have a Natural Expansions that is defendable, build the canons there instead of the main base, and secure your natural.
2. Gas up, build more canons, expand to natural if it's defendable
3. By this time, the Zerg player will have given hope on ground assult. 5 canons are pretty much impassable... the Zerg will go for Mutalisks/Corruptors
4. Mass up on Pheonixes - build 2-3 Stargates and pump Pheonixes using Chrono boost. You will encounter some Muta resistence, but you can build Pheonixes faster than he can build mutas.
5. By the time you have control of the skies, build Voidrays and gg

What is its weak point? How can I defend against it playing Zerg? Nydus/Overlord transport ?

When I play a 1v1 match against Zerg as Protoss, I'm happy. So far (in about 5 matches), I found the following strategy undefeatable:

1. Quickly build a Forge (before Gateway), then 2-3 cannons at your doorstep. If you have a Natural Expansions that is defendable, build the cannons there instead of the main base, and secure your natural.
2. Gas up, build more cannons, expand to natural if it's defendable
3. By this time, the Zerg player will have given hope on ground assault. 5 cannons are pretty much impassable... the Zerg will go for Mutalisks/Corruptors
4. Mass up on Phoenixes - build 2-3 Stargates and pump Phoenixes using Chrono boost. You will encounter some Muta resistance, but you can build Phoenixes faster than he can build Mutas.
5. By the time you have control of the skies, build Voidrays and gg

What is its weak point? How can I defend against it playing Zerg? Nydus/Overlord transport ?