Diminished chords are versatile chords. They're like portals that can lead you in so many directions. It's definitely a strange-sounding chord if you're not used to hearing music with tension. You'll find it in jazz, classical, metal, rock, and blues! It's a chord that creates movement. There's nothing wrong with playing just “pretty” chords, but when you play a chord that sounds “ugly” that leads into a pretty-sounding chord, suddenly it's like that chord became way more special. If we played just pretty sounding chords all the time, it would be kind of hard to appreciate them until you have a chord that creates tension. Sometimes adding too much spice can ruin a dish, so it's definitely a chord you'd handle with some care. When you start to get into 7th chords, a chord that is made up of four notes, you'll come to see that the V and vii° chords are related. D F# A C = D7 _ F# A C = F#° aka diminished The F# diminished chord, aka the vii°, can be seen as a rootless V7 chord, aka our D7. So we can imply that it's a V chord of some kind. But there's a bit more to diminished chords than just being related to the V chord. That's a discussion for another time, maybe. But knowing these chords, Sean has been discussing how they can lead you into chord functions. Each chord has a certain type of function. You'll start to recognize them everywhere, no matter what genre of music you listen to. Most music can be seen as I, IV, and V chords in some way. Again, a discussion for another time. Maybe I'll make a post going through all these chords in real world examples. I sorta hinted at this with different uses of the ii and iii chords in previous post a few months ago, but talked about approaching them a different way. But first it would be best just understanding them before pulling a Steely Dan type thing.