Steve Bunce wonders if we should get used to seeing Floyd Mayweather in unconventional fights, as he prepares to face kickboxing sensation Tenshin Nasukawa. (2:19)

Are Mayweather's unconventional fights a sign of what's to come? (2:19)

Whether you like it or not -- or if you had forgotten about it altogether -- Floyd Mayweather will be engaging in what is being described as a "three-round exhibition" on the RIZIN 14 card, which features a full ledger of MMA bouts on New Year's Eve at the Saitama Arena in Saitama, Japan.

No, Mayweather is not doing any grappling or kung fu, but he will be boxing against the noted Japanese kickboxer Tenshin Nasukawa.

But don't mistake this for Muhammad Ali-Antonio Inoki or even Mayweather-Conor McGregor. This won't be quite the spectacle of the former, and it won't even count on the official records the way the latter did.

When this event was first announced in early November, many believed Mayweather (who has a perfect mark of 50-0, 27 KOs, as a professional boxer) would actually be engaging in a kick-boxing contest. (OK, now THAT would've been interesting) Soon, Mayweather, announced that he was pulling out of this event given the misunderstanding.

But just as quickly, this matchup was revived, and a special set of regulations was drafted to assuage Mayweather and salvage the pairing.

The basic rules are this:

Three three-minute rounds are scheduled

Both Mayweather and Nasukawa must follow boxing rules

RIZIN 8-ounce gloves will be used

This bout will be contested at the welterweight limit (147 pounds)

There will be no judges involved

And as noted, this will not go on any boxing or MMA official records. Again, just good clean fun on New Year's Eve.

This in many ways would be like LeBron James playing Alexander Ovechkin in a game of one-on-one hoops.

You could say this is a version of un-mixed martial arts given the rules involved.

So, this is what we really know:

Where: Saitama Super Arena, Saitama Prefecture, Japan

When: Monday, Dec. 31, 1 a.m. ET

What: RIZIN 14 (14 fights, including Mayweather-Nasukawa)

How to watch: FITE PPV ($19.99) to air all fights, but the Mayweather-Nasukawa bout will be blocked in the U.S., Mexico, Canada and Japan)

Who's Nasukawa? Nasukawa was born in 1998 and was trained in karate and kickboxing from an early age by his trainer/father. Tenshin made his professional debut in 2014 at the age of 15 and has since claimed multiple world championships in kickboxing while remaining unbeaten. Tenshin is now the face for the Rizin Fighting Federation and their biggest headliner to date. Now at only 20, Tenshin is a Japanese sensation.

What's Rizin? Rizin Fighting Federation has held 15 mega-events since the promotion's debut in December 2015. Rizin is now recognized as the most watched combat sports event in Japan since Pride Fighting Championship. RIZIN has been a staple on prime-time Japanese national television with a five-hour New Year's Eve slot and watched in over 5.5 million households.

What are they saying: "This is a great way for me to go out there and give people some entertainment. It's an exhibition match, but it's giving me a chance to do something different." -- Mayweather.

"There's never been a Japanese fighter to face Floyd Mayweather in the ring. As an athlete, this is something that's a great honor and a challenging task. I'd like to make a big impression." -- Nasukawa.