What are all those X's in the title? They're a rhythm.
Try clapping that rhythm and see if you can identify it. Try it twice through, repeated exactly. The capital X's are accented, but each x takes the same length of time. They represent eighth notes in a four quarter measure.
If you're having trouble counting them, there are eight X's per measure. In the first, accents are on 1, 3, 6, and 8. In the second, 4 and 6. This is really syncopated: Natural accents are on odd numbered beats, which only the first two X's are on. This is one reason it sounds cool. The other is the way the accents are all paired.
From what I can figure out, this rhythm originally showed up in a song by Israel "Cachao" Lopez, a Cuban double bassist who was one of the inventors of Mambo, called Chanchullo. It dates from the fifties. The rhythm is played on piano with the melody (aside from vocals) played n high flute.
In the early sixties a Puerto Rican songwriter/bandleader/timbale player born in New York who knew Cachao, Tito Puente, wrote another song with that rhythm and, in fact, the same chord changes, plus pretty much the same instrumentation. It may sound familiar. It's called Oye Como Va.
Here's a recording with Tito Puente featuring Cachao as guest bassist:
The recording starts with a bass solo, and at the four minute point, Tito calls Oye Como Va.
The song was well known in his circles but not by the public at large until the late sixties, when it was covered by a rock group out of the Bay Area, resulting in Tito getting Way more substantial royalty checks. The group is of course Santana. The Santana version is actually extremely faithful to the original in terms of what's played when. What's radically different is On What.
Santana kept the timbales. It's a big part of their sound. The piano was replaced by organ going through a Leslie. For,those of you who don't know what a Leslie is, it's a speaker cabinet in which the speaker or some device controlling the speaker's output physically rotates, giving a sound a little similar to tremolo but not quite. It's most typically used on organ. To illustrate a Leslie sound, here's a great example, starting at precisely 57 seconds in. This is not Santana, it's Steppenwolf.
What's unusual about substituting organ through Leslie for piano is that piano is in part a percussion instrument. Organ is not. The beat is established by an instrument that is not percussive, at least not in this usage. And yet it completely works.
Organ instead of piano is one major substitution. The other is replacing flute with electric guitar. Most players would have a hard time doing this justice but Carlos Santana isn't Most Players, he's probably the most lyrical guitar player of his generation.
I saw Santana play live once. It was in the early seventies in the summer while I was in college. I lived in Maryland. My best friend , a guitarist and bass player I'd be in a band with for a little while after we graduated, and I were painting houses. In the evenings we'd often go up to Meriwether Post Pavillion in Columbia to catch rock concerts. Lawn seats were three bucks, so it was about as expensive as a movie.
If the act was one we really wanted to see, we'd spring for actual seats closer to stage. Such was the case with Santana. Unfortunately, events that summer during the Santana concert and I think Edgar Winter led Meriwether to change its programming away from rock for many years, and also to institute a policy of checking every container coming into the facility. It wasn't easygoing any more and felt very Police State.
The events in question were the place being crashed. Once that happened, the place was so mobbed that my friend and I had to stand on our seats to see, fairly good center seats pretty close, and three people stood on two seats because of how crowded it was. Having paid for the seats I was kind of pissed. I turned to the guy next to me, other side from my friend, and said "They should put barbed wire around this place." He opened his hand. His palm was cut open and bleeding.
"How'd you do that?"
What could I say? It was Santana.