Bo Ryan and his father, Butch, were inseparable. The man who taught basketball to underprivileged kids outside of Philly also taught his son the game, and eventually that son became a coaching legend.

Courtesy the Ryan Family

So as coaches do, Bo Ryan would attend every Final Four. And by his side, without fail, was Butch. Bo took him to the event every year as a birthday gift, starting in 1976. They'd sit together and talk hoops and watch a national championship game that one day the son would be coaching in.

As it turns out, today is that day. But Butch is not there to witness it. The man who earned a Bronze Star during World War II passed away at the age of 89 in the summer of 2013, just nine months before his kid led Wisconsin to last year's Final Four. It was Bo's first trip as a Division I coach, but he had participated in several Division III Final Fours as a coach at Wisconsin-Platteville, where he won four national titles in the 1990s.

After the last Division III title, Butch was right there in the middle of the celebration, holding up a sign that read "Bring on Duke!"

So, all these years later, with Bo finally getting that chance at Duke in a title game, North Carolina coach Roy Williams initiated a touching gesture.

Sect. 140, Row A, Seat 13 will be left open for tonight's game. Roy Williams has donated that seat to the memory of the late Butch Ryan. — Wisconsin Basketball (@BadgerMBB) April 7, 2015