Pokemon Side Stories tells the tales of many events that happen in parallel with Satoshi (Ash) and his journey. The tales range from what his old Pokémon are doing in Ookido’s (Professor Oak’s) lab, to the origins and secrets of Rocket-dan (Team Rocket), and the lives of past trainers he met such as Takeshi (Brock), Kasumi (Misty), Kenji (Tracey Sketchit), Hiroshi (Richie), and Shigeru (Gary Oak). Each episode tells a chapter in that person’s life.
Note: In Japan Pokemon Side Stories was broadcast as part of Shuukan Pokemon Housoukyoku. Shuukan Pokemon Housoukyoku (Weekly Pokemon Broadcasting Station) was a 91-episode live-action TV show that sometimes broadcast Encores (recaps) and exclusive Side Stories.
Since most of the episodes are not new Anime content but Live-Action, they are not listed here. Only those episodes that are Anime and are new (not previously released) are listed here under the name they were broadcast, “Pokemon Side Stories”.
Pokémon Chronicles, how the show was called in the U.S., shows the episodes from Pokemon Housoukyoku as well as specials from the original Pokémon Series AND Pokémon OVAs. These items are added to the database as they were released in Japan, so the order is slightly different.
Descriptions taken from AniDB.net