The Cubs-White Sox rivalry was too suffocating for Derrek Lee to truly enjoy it. “It just gets to be kind of a headache,” he once said. Paul Konerko once described a City Series showdown as bigger than a sporting event. “It’s not really a game,” he said. “It’s more like a saga.”

Headache or not, the saga continues Friday at Wrigley Field when the Cubs and Sox meet for Round 1. Here’s an A-Z City Series primer for those who missed the first 21 years:

A.J.: Cubs catcher Michael Barrett punched Sox counterpart A.J. Pierzynski in the head in 2006 at U.S. Cellular Field, igniting a full-scale brawl on the most memorable day in City Series history. A.J. remains the “face” of the Series, no pun intended.

BP Cup: The Cubs and Sox marketing departments teamed up in 2010 to find a sponsor for a City Series trophy. They found one in BP, but the company’s massive oil spill in the Gulf of Mexico in April of that year quickly turned the trophy into a running joke. Now it’s simply called the Crosstown Cup. The Cubs poured beer in the Cup after winning last year, but it leaked through the bottom.

Caruso: Slap-hitting Sox shortstop Mike Caruso hit seven career home runs in three seasons. But his game-winner against closer Rick Aguilera after a long rain delay at Wrigley on June 12, 1999, capped a stunning Sox sweep.

Drinkfest: The one commonality between Cubs and Sox fans is their seemingly unquenchable thirst. That sometimes has led to fights in the stands, particularly one in the upper deck at Sox Park a decade ago.

E: Eloy: The Cubs traded top prospect Eloy Jimenez to Sox in the Jose Quintana deal last July. Now he’s tearing up Double-A Birmingham and could be called up by Sept. 21, when the Sox and Cubs begin Round 2 at Sox Park.

Foster: Late Cubs pitcher Kevin Foster, an Evanston native, won the inaugural City Series game in 1997 at new Comiskey Park, then trashed Sox fans: “I thought it was going to be sold out. That says something about Sox fans. I believe if this game was at Wrigley Field there wouldn’t be a seat open. I believe that we have more die-hard Cubs fans than Sox fans.”

Graffanino’s gaffe: Sox third baseman Tony Graffanino committed a mental gaffe in the 20th inning of a tie game at Wrigley in 2001, believing a force was in play and neglecting to tag baserunner Eric Young at third. The Sox lost on Matt Stairs’ sacrifice fly.

Hawk: Sox announcer Ken “Hawk” Harrelson loves to troll Cubs fans during telecasts, including his memorable rants about John Lackey last year. Harrelson told the Tribune Lackey was “full of (bleep) and always has been.” The Hawk later vowed to “never step foot” in Wrigley again.

Ivy: The so-called “Ivy Game” at Wrigley in 1999 turned on a ball that rolled into the ivy, causing a ground-rule double that denied the Sox a run in the loss. Cubs first baseman Mark Grace credited Bill Veeck, who helped plant the ivy in 1937, with the victory.

Jerry: White Sox Chairman Jerry Reinsdorf has bragging rights over the Cubs’ three owners during his tenure with a 58-54 record since ’97. During the first series, he said Cubs fans were “very enthusiastic,” adding: “Sox fans are more demanding. They’re more knowledgeable about the game.”

Konerko: Konerko averaged one home run for every 13 at-bats (20 homers, 260 at-bats) against Cubs pitching, yet the Cubs honored him before his final game at Wrigley in 2014. Hit in head by a Kerry Wood curve in 2002, he responded with two home runs.

Lou: Cubs manager Lou Piniella was always a bit feistier come City Series time, whether it was calling Milton Bradley a “piece of (bleep)” in 2009 after a dugout tirade by the mercurial outfielder or ripping Sox announcer Steve Stone over criticism he wasn’t playing outfielder Tyler Colvin enough.

Milton: After Piniella called him an expletive (see “L”), Milton Bradley was surprisingly calm the next day: “To me, Lou Piniella is somebody. If it’s a motivating tactic and he’s taking a different switch since people are saying he didn’t have fire, then I understand.”

Navarro: After the Sox signed him in ’97 to a four-year, $20 million deal, former Cubs pitcher Jaime Navarro said he wanted “to show them what they’re missing on the North Side.” Navarro showed them, allowing six runs in the first three innings to register the first loss of the City Series.

Ozzie: Former White Sox manager Ozzie Guillen hated the cramped visitors clubhouse and outdated facilities at Wrigley Field. He called it a “dump” in 2011, but added: “As soon as the game starts, it’s one of the best places I’ve ever managed or played at in my career.”

Pick: “The Pick” occurred in 2000 at Wrigley when Sox reliever Sean Lowe picked Mark Grace off first base with a one-run lead to end the eighth. Grace claimed the Sox got a hometown call on what should’ve been called a balk.

Quintana: Cubs starter Jose Quintana wanted to pitch against his former team last year after arriving in a trade after the break. But the rotation was altered, leaving Quintana out. After pitching on Wednesday, he will miss this series too.

Rats: Guillen’s annual tale of seeing rats at Wrigley Field took on a life of its own. “The rats are bigger than pigs,” he claimed in 2008. “You want to take a look? I think the rats out there are lifting weights.”

Sammy: In the inaugural game at Comiskey Park in 1997, Cubs fans chanted “Sam-mee, Sam-mee” with Sosa at the plate, and gave him salaams after a running catch. “I don’t think I’ve had that happen before,” Sosa raved. It was Sosa’s first game against the Sox since they traded him just before the 1992 season, and Sox fans booed him loudly. “Fans always say whatever they want,” he said “But the bottom line is they still love you.” With

Theodore: Ted Lilly’s given name was Theodore Roosevelt Lilly, as Piniella often reminded reporters. Lilly came closest to throwing the first no-hitter in City Series history in 2010, before Juan Pierre’s leadoff single in the ninth broke it up.

Umpires: After Ross Gload of the Sox hit a first-inning grand slam off Carlos Zambrano at Wrigley in 2004, Cubs manager Dusty Baker appealed. The umpires convened, and the slam was changed to a foul ball. “That might have been the biggest hit I’ve ever had,” Gload said. “I already had run around the bases in front of 40,000 people, been mobbed at home plate.”

Valentin: Sox infielder Jose Valentin caused some controversy in 2001 when he imitated Sosa’s chest-bumping, air-kissing routine after a home run.

Wrigley: The Sox’s home ballpark has been called new Comiskey Park, U.S. Cellular Field and Guaranteed Rate Field during the first 21 years of the City Series. The Cubs have stuck with Wrigley Field … so far.

Xavier: Cubs outfielder Xavier Nady left his mark in a 2010 game at Wrigley when he let Konerko’s fly ball drop in front of him for an RBI single, bringing home the eventual winning run. Should “X” have caught it? “Look, it was a ball hung up there a long time …” Piniella sighed.

Yu: Cubs starter Yu Darvish is on the 10-day disabled list with the flu. If he recovers in time, he could pitch in Round 2 in late September.

Zambrano: Excitable starter Carlos Zambrano engaged in a shouting match with teammate Derrek Lee in 2010, upset over the Cubs’ fielding during a four-run first. “If you’re not going to play for me, then I’m not going to play for you,” Zambrano yelled. “Big Z” was suspended for his actions.