Harrison Shimazu looked at why the I – bVII – I chord progression was so important in Pokémon, specifically the Gen I games:
In a major key, we expect to hear a major seventh (ex. B natural in the key of C) instead of a minor seventh (ex. Bb in the key of C). Therefore, the bVII chord — which is built on the minor seventh — tends to catch us by surprise. While the flattened scale degree feels darker than what we’re used to hearing in a major key, the major quality of the triad prevents it from sounding dissonant or sinister. The emotional end result is something that’s a little perilous but overall proud and optimistic — a perfect color for conveying the feeling of adventure.
A major scale with a flattened seventh is also referred to as the “mixolydian mode,” and it would be totally fair to analyze a lot of tunes in the Pokémon soundtrack using this mode. Speaking of which, now that we have an idea of what the chord progression sounds like, let’s dive into three themes that appear across the entire Pokémon franchise that are defined by it.