Super Mario World 2: Yoshi's Island is a platforming video game developed and published by Nintendo for the Super Nintendo Entertainment System. It is a sequel to Super Mario World which was Yoshi's first appearance. Instead of playing as Mario, the player takes control of various Yoshis while Mario appears as a helpless infant. Yoshi's New Island has a total of six worlds. Each world contains a total of nine levels, one of which can only be unlocked by getting all the Stars, Red Coins, and Flowers in each level of said world. Yoshi's Island U is an action-adventure platforming video game, the sixth title in the Yoshi's Island series, and the second for the Wii U, and it also has a HD port for the Switch. It is planned to be released on July 12 in the Americas, August 5 in Europe, September 7 in Australia and September 12th in Japan.

Two of my co-workers, PC editor Jeff Grubb and head of social media Anthony Agnello, are going to take part in a panel at PAX East in Boston next month to debate which games count as “core” to the Mario series. This debate has been raging on for some time now, and Jeff and I have discussed it ourselves on the GamesBeat Decides podcast.

I will not be at PAX East this year, so you won’t hear me scream my opinions during the panel. Honestly, I think that most of the selections should be obvious. I can’t get mad if you say Super Mario Sunshine isn’t a core Mario game, because the idea is preposterous. Other titles, like Mario vs. Donkey Kong, are so far removed from the traditional series tropes and mechanics that there’s no real danger of anyone considering them.

But then there’s Yoshi’s Island. Or, as some would love to remind us, Super Mario World 2: Yoshi’s Island. Its status is one of the most hotly contested. And while I won’t be at PAX East, I want my colleagues to know that I firmly stand in the “no, it’s not core” camp.

Let me be clear. Yoshi’s Island is a fantastic game. It’s one of the greatest 2D sidescrollers ever. But being a core Mario game isn’t about quality. I have three simple rules for what makes a core Mario game.

1. Mario is in the name.
2. Mario is in the principal character, meaning the one the player controls most often.
3. Mechanically, it plays similarly to the traditional 2D (as started in Super Mario Bros.) or 3D (as started in Super Mario 64) molds.

This is how I come to my list of core Mario games, which Jeff and I agreed on. It also disqualifies some contested titles, like the original Donkey Kong, which does not have Mario in its name. Nor does it play like other 2D Mario games. Yoshi’s Island also betrays two of mycriteria. Mario is not the principal character. You only control him for brief periods of time. Overall, it accounts for probably less than 1 percent of the entire game. Yoshi’s Island also has its own 2D physics, controls, and overall gameplay feel when compared to other core 2D Mario games. It was so distinct that it started its own series of Yoshi’s games, which include Yoshi’s Story, Yoshi’s New Island, and Yoshi’s Woolly World.

Above: Is this core too?

This is actually the same trajectory that the Wario series followed. The first Wario Land’s full title is Wario Land: Super Mario Land 3. It created its own 2D mechanics that stood apart from traditional Mario games, and it spawned its own franchise that immediately dropped the Super Mario Land branding. Few argue for Wario Land to be a core Mario game. If it contained a power-up that turned Wario into Mario for 30 seconds, would it suddenly then qualify for the Yoshi’s Islanders?

But even then, Yoshi’s Island status is in a way more precarious than Wario Land’s. Nintendo only branded the game as Super Mario World 2 outside of Japan. It was a marketing maneuver to more closely tie the title into the Super Nintendo’s successful launch game. So, in a way, Yoshi’s Island doesn’t even fit my first criteria.

Yoshi’s Island is a spin-off, the same as Wario Land, Super Princess Peach, or Captain Toad: Treasure Trackers. It is not a core Mario game. It is a Yoshi game. Calling it a core Mario title opens up the same problem as calling Pluto a planet; it opens up eligibility of too many others for the same qualification. If Yoshi’s Island is core, then why not Yoshi’s New Island?

So, esteemed panelists at PAX East, please take these proofs into consideration as you engage in your debates. Yoshi’s Island is a treasured classic. We love it. But that doesn’t mean we need to shove into some category it doesn’t belong in.

But have luck figuring out if Super Mario Maker counts. I’m still trying to figure that one out.

The RetroBeat is a weekly column that looks at gaming’s past, diving into classics, new retro titles, or looking at how old favorites — and their design techniques — inspire today’s market and experiences. If you have any retro-themed projects or scoops you’d like to send my way, please contact me.