A 10-game lead is pretty rare in the history of the Cubs franchise. Of course, a 10-game lead in a division isn't the same as a 10-game lead was in a single league, as baseball was divided before 1969. The Cubs' 40-16 record is currently 6½ games better than the next-best team in the N.L. (Nationals, 34-23 and Giants, 35-24). Even that's a pretty impressive lead for early June.
Cubs teams have had a lead of 10 games or more in a league or division just six other times before now (since 1900). Here are all of those years, all of which resulted in a postseason appearance.
1906: The Cubs went up 10 games on August 22 with a 4-3 win over the Phillies. They maintained at least that big a lead for the rest of the season, winning the N.L. pennant by 20 games.
1907: The Cubs went up 10 games by sweeping a doubleheader over the Cardinals on June 26. The lead briefly went under 10 games a few days later, but went back to 10½ games on July 3 and stayed there the rest of the year. They won the pennant by 17 games.
1910: The Cubs beat the Phillies on August 30 to take a 10-game lead. There were a couple of brief dips to 9½ games after that, but they won the pennant by 13 games.
1918: This war-shortened season ended on September 2. The Cubs first took a 10-game lead on August 21, and won the pennant by 10½ games.
1929: The Cubs beat the Giants on August 21 to take a 10½ game led. The lead increased to as much as 14½ games; eventually they won the pennant by 10½.
2008: The Cubs clinched the N.L. Central title on September 21 with a 5-4 win over the Cardinals, putting their lead at 10 games with nine remaining. They kept at least a 10-game lead for three days, eventually winning the division by 7½.
And that's it. Six times before now -- and none of them as early in the season as June 6. So you are viewing something quite special.
There are a few other things about this Cubs season that eventually could set team marks. I've talked about walks; the Cubs are still on pace to break the team record (650, set in 1975). They came close in 2008 (638). They're currently on pace for 723 walks. The National League record is 732, set in 1947 by the Dodgers.
This Cubs team could also do something that's been done only twice by Cubs teams since 1937: score 800 or more runs. Their current total of 303 is 5.41 per game, which is a pace for 877. Last time a Cubs team scored more than that: 1930, which was a monster offensive season for everyone (the entire N.L. hit .303 that year). The Cubs scored 998 runs in 1930, which is their post-1900 high.
The Cubs' current run differential of +143 laps the field this year. Next best is the Red Sox at +69; next best in the N.L., the Nationals at +54. That's a differential of +2.55 per game, which, if maintained for the entire season, would result in a +413 differential. That would shatter the team record, +323, which was set in 1906.
There are also some individual marks to look for. All five Cubs starting pitchers have ERAs under 3.00. The last time that happened for a Cubs team was in the deadball era: 1916.
The Cubs currently have four players with 34 or more runs scored: Anthony Rizzo (34), Dexter Fowler (38), Ben Zobrist (39) and Kris Bryant (42). All of them are on pace for 100 runs scored. Since 1945, the Cubs have had more than one player score 100 runs in a season four times:
1969: Billy Williams (109), Don Kessinger (103) 1970: Billy Williams (137), Jim Hickman (102) 1984: Ryne Sandberg (114), Gary Matthews (101) 1999: Sammy Sosa (114), Mark Grace (107)
Needless to say, the Cubs have never come close to having four players score 100 runs in a single season. The last four Cubs players to score 100 or more runs in a season span the last 12 years (Dexter Fowler in 2015, Mark DeRosa in 2008, Derrek Lee in 2005 and Moises Alou in 2004).
The Cubs have three players on pace for 100 RBI: Anthony Rizzo (42), Kris Bryant (41) and Ben Zobrist (35). This has happened twice in Cubs history since 1930. In 1970, Billy Williams had 129 RBI, Jim Hickman 115 and Ron Santo 114, and in 1965, Williams had 108, Ernie Banks 106 and Santo 101.
The 2016 Cubs have a chance to do things that haven't been done in decades, or in some cases, ever. And of course, to win the World Series.