Okay, so Tuesday night, instead of Bryce Harper, Jayson Werth, and Denard Span, the Nationals played Eury Perez, Tyler Moore, and Steve Lombardozzi. Theirs was not a particularly good lineup opposite Clayton Kershaw and the Dodgers, so perhaps it wasn’t surprising that Kershaw was dominant for an out shy of nine innings. It should probably never be surprising when Kershaw is dominant, because he’s a dominant pitcher with dominant stuff, and by the way, he’s younger than A.J. Griffin. His final line on Tuesday included a walk and 11 strikeouts, with 96 strikes. The last pitcher to throw that many strikes in a game was Justin Verlander in 2012. In 2010, Brandon Morrow threw 97 strikes in a near-no-hitter. After that you’re going back to 2002. Tuesday night, Kershaw was on top of Sandy Koufax’s game.

As is the case with all players who have established themselves as terrific, it’s easy to take Clayton Kershaw for granted, to not appreciate him as much as he ought to be appreciated. One can’t really help it, because that’s just how the brain works, but one can pause to step back and consider of how much a given player is capable. Here I feel like pausing over Kershaw, and I also feel like committing a lot of attention to his curveball, because the pitch was aces for him Tuesday and because a Clayton Kershaw curveball is one of baseball’s signature experiences. Kershaw’s about a lot more than his curve, but allow me this freedom.

The first memory I think a lot of people have of Kershaw is a curve he threw to Sean Casey in 2008 spring training. Granted, people were familiar with him before as a draftee and as a prospect, but the Casey curve turned into a baseball viral video before those things really took off. A lot of people knew what Kershaw was about, but this pitch provided visual evidence. This pitch made Vin Scully temporarily lose control of his restraint, at the beginning of March. This pitch earned a Scully nickname before it had ever once been thrown in the major leagues.

And that curveball has never not been dominant. The usage pattern has fluctuated, but, well, Kershaw’s career aligns nicely with the PITCHf/x era. He broke in in 2008, and his pitches have always been easy to classify. So we have basically a complete history of Kershaw’s pitching, broken down by pitch. According to Brooks Baseball, he’s allowed dozens of home runs off of his fastball. He’s allowed 17 off of his slider, and three off of his infrequent changeup. He’s allowed one home run off of his curveball, ever. He’s thrown almost 2,000 of them. It came in the 2009 playoffs, meaning Kershaw has never allowed a curveball home run in the regular season. The curveball homer was hit by Matt Holliday, and he was out in front of the pitch, barely leaving the yard. Even this curveball wasn’t confidently blasted.

Tuesday night, Kershaw had his curveball working. He usually has his curveball working, and Tuesday, in fairness, he had all of his pitches working. But he used that curveball to generate seven of his 11 strikeouts. He threw the pitch 21 times, picking up 17 strikes. Seven of the strikes were cut on and missed, and only two of the curves were hit into play. Just about every single time, Kershaw’s curve had the Nationals hitters off balance, and this is a pitch for which Kershaw is widely known.

FanGraphs offers a Pitch Value section, and to be honest I don’t look at it very much. There are problems with pitch classification, and there are matters of game theory to take into account — pitches aren’t to be evaluated in isolation, not statistically, because every pitch thrown depends on other pitches. Pitches are also used differently, thrown in different counts, so pitch values can provide only a rough approximation of pitch quality. But with all that said, since 2011, per 100 pitches, Clayton Kershaw has thrown baseball’s most effective curveball. You can poke holes in the numbers if you like, but this one at least passes the smell test. It passes every test.

I was asked in my most recent FG chat about my favorite kind of baseball play to watch. Few things, to me, can top a rangy shortstop making a play way to his right or left. Like everybody, I’m fond of a good clobbered home run, and I’m a sucker for a high fastball that’s cut on and missed. But I melt at a sweeping, perfectly-located curveball. It’s when I find baseball is most like an art form, and no one’s curveball tickles my senses quite like Kershaw’s does. At least not nearly so consistently.

Kershaw, of course, was drafted with a fastball and a curveball. When he showed up in spring training 2008, he threw a fastball and a curveball. His first year he threw a curve just about a quarter of the time, and he was good, but sometimes wild. Soon thereafter Kershaw added a slider, and that became his primary breaking ball. His curve usage dropped all the way to 5% in 2011, but it’s since doubled, and Kershaw features the pitch most eagerly and prominently in two-strike counts. Kershaw no longer has to depend on his curve as his only other offering, and that’s allowed his curve to get better.

In an article from June 2011:

The biggest adjustment came this year when [Kershaw] added a slider in part because, “I couldn’t control my curveball.” Manager Don Mattingly agreed, but added, “No one [umpires] calls the curveball [for strikes] anymore. No one swings at it. So, you can’t throw it. But his slider and changeup have become very good.”

It’s pretty evident how Kershaw’s curveball has benefited from a broader arsenal. Below, you’ll see swing rates against the curve over the years:

2008: 28%

28% 2009: 27%

27% 2010: 24%

24% 2011: 32%

32% 2012: 37%

37% 2013: 45%

It’s not a criticism of the curve that Kershaw needed to add another pitch. But he had such a velocity difference between his fastball and his curve that it was relatively easy to know when the curve was coming, and where it was going to end up. Kershaw’s first three years, his curve went for a strike 49% of the time, and batters made 69% contact. The last three years, it’s gone for a strike 54% of the time, and batters have made 59% contact. Batters swing at the curve more now, and there’s still not much of anything they can do against it.

At this point, Kershaw’s a complete pitcher, with a complete repertoire that still features the curve that made him famous. Gone is the wildness, gone are the pitch-count restrictions, gone are the questions of potential. Tuesday’s 132 pitches were a career high for Kershaw, and a season-high for Major League Baseball. His last pitch was a fastball at 93 miles per hour; his penultimate pitch was a heater at 94. Kershaw is riding an active streak of 21 consecutive starts allowing three or fewer earned runs. In 2010, Mat Latos had a streak of 22 such starts, but no one’s reached 23 since Pedro Martinez had a streak end in 2000. No one’s surpassed 23 since Greg Maddux had a streak end in 1994. We don’t know if Clayton Kershaw is the best pitcher in baseball. That’s kind of the whole point.

On Tuesday, Kershaw reached 1,000 career regular-season innings with a first-inning strikeout of Danny Espinosa. He stands now at 1008.1, with 1041 whiffs. This is his sixth big-league season, and he’s allowed a career OPS+ of 69. Covering the Expansion Era, going back to 1961, here are the lowest OPS+ figures allowed by a pitcher over his first six big-league seasons, understanding that Kershaw’s is still active:

And over the past calendar year, no one in baseball has thrown more innings. Kershaw wouldn’t be the pitcher he is today had he not taken the time to implement a slider and improve his changeup. That was necessary over the course of his development, if he wanted to achieve his full potential. But it was the curve that really got Kershaw noticed, and it’s still the curve that Kershaw likes to look to when he’s got a hitter on the ropes. When Kershaw’s ahead, or when there are two strikes, hitters can’t be sure if they’ll see a curveball or a slider. And that’s only worked to the benefit of both. Over the past three years, Kershaw has ended 200 at bats with curveballs. Of those at bats, 19 have ended with hits, and 122 have ended with strikeouts.

In the month of June 2010, Clayton Kershaw posted a 3.63 ERA. That’s his worst mark in a month in more than four calendar years.