Detroit in the dark (blue) jerseys, Chicago in the white
November 29, 1934: For the 1st time, an NFL game is broadcast nationwide on radio. In fact, that's why it's played at all: To sell radios.
George A. Richards owned Detroit radio station WJR, 760 on the AM dial, an affiliate of the NBC Blue Network, which later became ABC. He bought the NFL's Portsmouth Spartans, who had momentary success by reaching the 1932 NFL Championship Game, but losing it to the Chicago Bears. But they could never get fans in Southern Ohio.
So Richards bought the team, brought them to Detroit, and renamed them the Lions, to tie in with the city's baseball team, the Tigers, and because the lion is "the king of the jungle," and he wanted to build a team that would be "the king of the NFL."
Next up, on Sunday, December 2, at Wrigley Field in Chicago, was a game against the team that had won the 1st 2 NFL Championship Games, the previous year against the Giants and the year before against the Spartans/Lions. It was the Chicago Bears, with 2 legends in their backfield, Harold "Red" Grange and Bronislau "Bronko" Nagurski.
Richards knew that Thanksgiving was coming up, the ultimate family holiday. When everyone would be gathered around the radio. (No television in those days.) Maybe if there was a special program on the day, more radios would be sold, and Richards would make more money.
So he talked to Bears owner-coach George Halas about adding a game between the teams, on Thursday, in Detroit. (Up until 1940, Thanksgiving Day was always on the last Thursday in November. Since then, it's been the 4th Thursday in November.) Halas, having played and coached in several Thanksgiving Day games over the years, and hardly opposed at the time to playing games so close together, liked the idea. He didn't care about selling radios. He did care about selling the Bears (to fans, not to any one person) and selling the NFL. So he talked the other NFL owners into allowing it.
It worked like a charm: One of the biggest national audiences in radio history was tuned in, and over 26,000 fans crammed into the small stadium. And it looked like the Lions were living up to their responsibility, taking a 16-7 halftime lead, thanks to 2 touchdowns by LeRoy "Ace" Gutowsky.
But Jack Manders, so accurate he was known as "Automatic Jack," kicked 2 field goals in the 3rd quarter to close within 16-13. And in the 4th quarter, Joe Zeller intercepted a pass from Glenn Presnell and returned it to the Lions' 4-yard line. You wouldn't expect Nagurski to pass for a touchdown, but he did, to Bill Hewitt. Despite being held to 116 rushing yards, the Bears beat the Lions, 19-16.
Three days later, at Wrigley, the Bears beat the Lions again, 10-7. The Lions had started 10-0, but ended 10-3. In contrast, the Bears finished the season at 13-0, and as Western Division Champions. This time, though, they lost the Championship Game, to the Giants.
They would go undefeated and then lose the Championship Game again in 1942. It would take until the 1972 season for a team to have an undefeated regular season and then win the NFL Championship, as the Miami Dolphins won Super Bowl VII.
But the Lions turned Detroit on to pro football, after the failure of 3 different NFL teams: The Heralds (who changed their name to the Tigers for their 2nd season) in 1920 and '21, the Panthers in 1925 and '26, and the Wolverines in 1928. In 1935, the Lions were less impressive in the regular season, going 7-3-2, but beat the Bears on Thanksgiving, and then beat the Giants to win their 1st NFL Championship.
The Lions continued to play on Thanksgiving until 1938, playing the Bears each time, then resumed in 1945, and have played on the day every season since. Counting their 2021 loss to the Chicago Bears, a far more dire contest than the 1934 inaugural, they are 37-43-2 on T-Day. Of their 82 games, 21 have been against the Green Bay Packers, and 19 against the Bears.
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November 29, 1934 was Thanksgiving, and therefore a Thursday. There were 2 other NFL games that day. The Chicago Cardinals beat the Packers, 6-0 at Comiskey Park in Chicago. And, in a football version of the great baseball rivalry (but different organizations in each case), the New York Giants beat the Brooklyn Dodgers, 27-0 at Ebbets Field.
Baseball was out of season, and the NBA wasn't founded yet. There were 2 NHL games, and Detroit and Chicago were involved, but not against each other. The Detroit Red Wings lost to the Montreal Maroons, 2-1 at the Montreal Forum. And the Chicago Black Hawks lost to the New York Americans, 2-0 at the old Madison Square Garden.
Of course, by 1942, both the Maroons and the Amerks would be out of business. In contrast, the Red Wings and the Blackhawks (they switched to writing it as 1 word in 1986) are still at it today. And it's a better Detroit vs. Chicago rivalry than Lions vs. Bears, or Tigers vs. White Sox, or even Pistons vs. Bulls.