By the time we reached the fourth generation of Pokémon, it was assuredly a worldwide phenomenon. We were hitting double digits of mainline games and adding in a wealth of spinoffs ranging from pinball to photography. But a transition was ahead for Nintendo and the Game Boy line that Pokémon owned since the moment it launched. The Game Boy Advance was about to have a shortened lifespan as the Nintendo DS launched in North America at the end of 2004. Around the end of that year is when Nintendo started to talk about that new handheld system’s first mainline Pokémon games. This was still the era of wide gaps between the Japanese release of games and the rest of the world, so while Pokémon Emerald was still nearly a year away from launching outside of Japan, Nintendo and The Pokémon Company started talking about the debut DS line of Pokémon games, largely because all they had at the DS launch was a Pokémon racing game, so they had to confirm that yes, the third pillar system was going to get a “real” Pokémon game.

Aside from that mention, it would take more than a year for Pokémon Diamond and Pearl to get a more formal reveal. Information started to get revealed in 2006, including the fact it will still use sprites and retain a lot of the familiar Pokémon battling and tropes. Back in the day, a lot of dissension cascaded through the Nintendo fandom. Was Pokémon getting stale? Was this just more of the same? The drum beat of new features kept thumping, as online was promised (via our old friends the Friend Code) along with touch screen interactions because this was a DS game after all.

As all this news was hitting, I was about as far away from Pokémon as I had ever been. I was 10 years old when the original games came to America and was completely done in by the marketing blitz, going deep into the game, the cards, and the anime. But as Diamond and Pearl were nearing North American launch in 2007, I was but a jaded college freshman who entered school thinking I wasn’t going to be as into video games as I was before. That was, if you couldn’t tell by the fact I joined Nintendo World Report a year after that, a bold-faced lie. Thanks to peer pressure, Pokémon was back on my radar. I told myself after I was done with finals, I would pick up Pearl. For reasons I cannot justify, I wound up buying the game before finals. I thankfully still passed but I got deep into the world of Pokémon again for the first time in years. It was glorious.

I haven’t revisited these specific games since this era, but they laid the foundation so strongly for modern Pokémon, with one of the biggest touches being the division of moves being categorized as physical or special. The story, while not a series peak or anything, started to zag a little bit with the tropes of the original. You had two rivals to contend with as you journeyed around Sinnoh trying to protect your legendary from Team Galactic. It also made use of the DS’s touch screen, even if we can rightfully look back on that as gimmicky nonsense. Online trading and battling also were featured thanks to the old Nintendo WiFi Connection and friend codes.

But aside from my personal sentimental reason for this game being the one that brought me back, I think this generation rocks largely because it has one of the best remakes in the entire franchise history in Pokémon Heart Gold and Soul Silver. Not only are Gold and Silver just a good foundation, as they include essentially all of Johto and Kanto from the first two generations, but it also became a keen vision of the future of Pokémon. Heart Gold and Soul Silver came bundled with the Pokéwalker, a pedometer with a little screen that you could use to bring Pokémon with you outside of the game. It had synergy with the game itself, as you could have any Pokémon be your partner one in-game. But beyond that, it was further baby steps for Pokémon Go, which was still six years from its debut when Heart Gold and Soul Silver launched in the west.

My memories of the Pokéwalker are extremely fond. By this point, I was fully back on my Pokémon fandom and a lot of my initial feelings on this are captured in my dual review of the two games with Zach Miller. I was at the end of college (I did not flunk out after getting Diamond and Pearl during finals two years prior) and wound up bringing that little pedometer with me virtually everywhere. It was an incredible extension of the game that, while naturally gimmicky in its execution, fit so well into the vibe of Pokémon. You were bringing your monsters with you in your pocket (or clipped to a belt). Seared into my brain is the experience of bringing the Pokéwalker on the Atlantic City boardwalk. I’d like to think I was the first person to bring a Pokéwalker to a bar.

I don’t necessarily have an impassioned plea for why folks should go back to play the fourth generation of Pokémon again, but I think fondly of this era because it’s when I got back into the series and it’s also when I feel the franchise fully solidified itself as a mainstay culturally and within Nintendo. Critical steps were made to move the games beyond its Game Boy origins and even connecting and extending the games past a console. Pokémon Go might not happen without the Pokéwalker. And without Pokémon Go, who knows what these games are now.