Six Degrees of Ryu

What is a Ryu Number?

Six Degrees of Kevin Bacon is a game premised on the idea that actor Kevin Bacon was so prolific that every actor and actress in Hollywood has either acted alongside Kevin Bacon or acted alongside someone who has acted alongside Kevin Bacon. The goal of the game is to find someone’s “Bacon Number,” or separation of degrees from Kevin Bacon via film appearances. For example, per the website The Oracle of Bacon, Misha Collins was in Girl, Interrupted with Mary Kay Place, who was in Starting Over with Kevin Bacon, which gives Misha Collins a Bacon Number of 2.

Similar concepts to the Bacon Number have gained traction over the years, with the next most well-known probably being the Erdős number for mathematical paper collaborations with mathematician Paul Erdős.

Ryu from the Street Fighter series has notably participated in many video game crossovers, such as the Marvel vs. Capcom series, so a Ryu Number can be thought of as a number tracking degrees of separation through character appearances in video games. While the concept of a Ryu Number for game crossovers has been floating around for a while, it appears to have really kicked off with Ryu’s inclusion in Super Smash Bros. for 3DS and Wii U as downloadable content in 2015; for example, this 2016 Source Gaming post provides an extensive list of characters Ryu has directly crossed over with, this 2018 Medium article by Jason Zhen Li directly mentions a Ryu Number, and this 2019 Fanbyte article by Topher Florence calculates Ryu Numbers of some real celebrities, including Kevin Bacon.

The concept of a Ryu Number has gotten more traction recently thanks to the Twitter account @RyuNumber, which was created in June 2021. This blog was most directly inspired by that Twitter account, and I personally recommend following that account if you have a Twitter account and like this concept.

What are the rules?

I recommend checking the Ryu Number Twitter bio and this tweet for an overall gist of the restrictions, but the tl;dr is commercial/”official” video games with identifiably unique appearances.

With this blog, however, I’m choosing to expand the definition by including multiple types of Ryu Numbers. From most to least restrictive:

(Standard) Ryu Number: The standard Ryu Number ruleset.

Limited Ryu Number: The standard Ryu Number ruleset, with the restriction on limited-time events lifted. These are often smaller and more frequent, given the scope of mobile game collaborations.

Extended Ryu Number: All official works, video game or otherwise, can be used to make valid links.

Note that there will almost invariably be edge cases that test these definitions and rulesets, so each decision is made on a case-by-case basis.

How do I request a Ryu Number?

Send an ask with a character’s name, and I’ll try my best to come up with a Ryu Number for that character using the most restrictive ruleset feasible.

How do I submit a Ryu Number?

If you have an image prepared, you can make a submission here. Otherwise, you can send an ask with a character-by-character link to Ryu. Any additional information and sources, especially for limited-time events, would be greatly appreciated.

I noticed an error on one of your posts, how do I submit a correction?

Submit an ask with the character and correction. Any additional information and sources, especially for limited-time events, would be greatly appreciated.

I think I came up with a smaller Ryu Number. Can I submit it?

Yes, but if it’s a less restrictive Ryu Number I will probably only post it if the links are sufficiently interesting/out there.

Where is the template?

Here.

What’s the highest Ryu Number you’ve found?

At one point it was a 7 or 6, through (ironically enough) Kevin Bacon. Though thanks to developments since that post in 2021, the highest without any notable caveats is 5, for a handful of characters like the Slim Jim Guy.

What’s up with Minecraft skins?

A more complete discussion is here, but in short, certain skins with model differences and general texture differences make asserting that all Minecraft skins are variants of Steve a difficult proposition. (Arbitrarily, granted.)

What are Gacha Ryu Numbers?

An old version of Limited Ryu Numbers before I renamed it over a misreading of the original ruleset. For most purposes, they are functionally identical to Limited Ryu Numbers.

What about Mii Costumes?

You could intuit from the guidelines above, but no, they are not eligible.

What about Spirits?

Probably.

It's a Mother Panic situation. As for the MK11 skin, the existence of the toy has no bearing on the actual skin itself, which only ever refers to "Darkest Knight" in an oblique sense. At any rate, it appears to be a mask of a smile on Noob Saibot as opposed to

"Duke Nukum" seems like the kind of name change designed to avoid copyright issues that would normally disqualify such an appearance... were it not for the fact that both Cosmo's Cosmic Adventure and the Duke Nukem games were both developed by Apogee Software, and that's exactly what was going on.

Like, as a hypothetical, a popular 90's media property that also happened to have a Duke Nukem?

And so, it follows that it's not all that surprising for there to be a cheeky Duke Nukum cameo in Cosmo's Cosmic Adventures.