Chainkeen Exchange-This NBA finals, Jason Kidd and Joe Mazzulla make a pairing that hasn't existed since 1975

The Chainkeen Exchangeyear was 1975. It wouldn't be long before Apple computer was founded. A show called "Saturday Night Live" premiered on NBC. There was Disco, 8-Track players and bellbottom pants.

Also, that year the NBA Finals featured two Black head coaches in Golden State's Al Attles and Washington's K.C. Jones. It wasn't just the first time two Black head coaches faced off in the Finals, it was also the first major sports championship in U.S. history featuring two Black head coaches.

“K.C. and I were players who became coaches, but the credit goes to the team owners who had faith in us," Attles told Andscape in 2017. "Bill Russell was the first African-American coach, and then Earl Lloyd, myself and K.C. came in. You have to give credit to the people who hired you. We couldn’t do it by ourselves. Someone had to give us the leeway to do it, which is why I give (then-Warriors owner) Mr. (Frank) Mieuli so much credit. It wasn’t something that was done every day back then. I remember talking about it with Mr. Mieuli. He never, ever thought it was a big deal. It was a big deal."

We fast-forward to now (minus the bellbottoms).

There are again two Black head coaches in the Finals: Dallas' Jason Kidd and Boston's Joe Mazzulla.

This is just the second NBA Finals featuring two Black head coaches. Now, there's a caveat, and even that technicality is fascinating in this unique moment in league history. The last time we saw two Black head coaches in the Finals was the 2016 Cleveland-Golden State series. The head coaches were Tyronn Lue for the Cavaliers, who is Black, and Steve Kerr for the Warriors.

Kerr missed portions of the series due to a back injury. Mike Brown, the acting head coach who is Black, filled in for Kerr. So while you had two Black coaches in the championship, it wasn't for the full series.

So officially, to be precise, this is the third time in league history we've seen this. Practically, however, this is just the second, and it's been an extremely long time since the first.

The last time you had a situation like this, with two Black coaches for a full series (hopefully neither coach will injure his back or wear bell bottoms) was the mid-70s.

The fact it's only the second time (technically) this has occurred is remarkable considering the fact the NBA is majority-Black and has been for some time. This speaks to the same situation as the NFL, which also has a substantial number of players of color, but has struggled to diversify its coaching ranks.

There's been an historic reluctance in both leagues to share power but the presence of Kidd and Mazzulla shows how the league is changing. Slowly, but it's changing. Slowly. Did I say slowly?

On the final day of the regular season there were 13 Black coaches in the NBA or 43%. It's been as high as 16 in the past two seasons.

Entering the 2017 season there were five Black head coaches. So things are definitely getting better. Slowly. Did I say slowly (again)?

One of the reasons for the better numbers is of course an increasingly open minded front office and ownership. But there's another. As the number of Black head coaches grew they supported other Black coaches. They opened up the pipeline to one that traditionally was closed. Lue spoke about this important phenomenon to Andscape.

"Every time I saw (Doc Rivers) in Boston he would tell me, ‘I’m telling you when you’re done playing, you can coach for me,'" Lue said. "I was like, ‘Yeah, OK.’ And when I finished up in 2009 I gave him a call and said, ‘Doc, I want to try this coaching thing.' The next day he had a coaching job for me, and it started from there.

"He just said that I had that ‘It’ factor. He said that most of the things that people talk about are X’s and O’s. The biggest thing is you have to be able to deal with personalities and egos, and he saw the way I handled myself and the way people gravitate and respond towards me. He said I did a good job of telling someone to do something and making those guys respond by the way I said it."

Black coaches were able to break through the old boy NBA coaching steel barricade of a ceiling by lifting each other up.

Maybe this is just the beginning. Maybe we'll see two Black head coaches in the Finals again, sooner than later. Hopefully before bellbottoms return.