Flamenco Guitar Techniques - Alzapua

Alzapua is a technique unique to flamenco. I personally liken it to the way oud players use the plectrum. Typically a single unit of alzapua sequence is made up of 3 components: Pulgar plays a bass note - Pulgar swings down to strike the lower two strings - Pulgar swings up to strike the same two strings ending up at the initial string where the action started. 

Again, I recommend practising alzapua with the metronome. The main aspect of alzapua to be remembered is that the action/force that drives the thumb comes from the wrist. Players do move their thumbs from the main joint to fine tune the action, yes, but the force is driven by the circular movement of the wrist. With enough exercise you can forget about the thumb and use your wrist's natural tendency to turn left and right to play crisp alzapua sequences. Once you find your wrist's natural range of motion and fine tune the twitch muscle that governs that movement, alzapua is not a very difficult technique and it sounds pretty flashy…

Alzapua can be enriched by adding legatos to the main bass note making it a 4-note sequence. Here is an example:

Alzapua is a very effective tool to play percussive sequences especially when coupled with golpes.  Here is such a passage by Manolo Sanlucar:

Alzapua will eat away at your thumb nail. It is common among flamenco players to coat their thumb nails with super glue. There are also nail kits with small silk stickers you can put on your nail as reinforcement before applying the super glue.

Here is the youtube playlist of atrafanaSchool on alzapua:
Alzapua Exercises

Also, check out the alzapua training package from the atrafanaStore.
Alzapua Training Package