Ichiro is one of the most bizarre players of the past 20 seasons. While many hitters have come over from Japan to the MLB, Ichiro has stuck in North America like no one else. The NPB is famous for its ground-ball-heavy approach—per Deltagraphs, the NPB ran a GB% of 48 percent compared to 44 percent for the MLB last season—but that approach usually doesn't work that well across the pond. That wasn't the case for Ichiro. He made it work, and he made it work all the way to capturing the single-season hit record. And he did it in a really, really weird way.
How to Hit in Japan
To explain why it was so weird that Ichiro did what he did, we have to go all the way back to the beginning, back to Ichiro's home country of Japan. Nippon Pro Baseball is the highest level of professional competition in Japan, and it's where MLB superstars (and future superstars) like Ichiro, Shohei Otani, and Hideki Matsui started their careers.
The NPB is traditionally referred to as an "AAAA league"—its level of competition is below that of the MLB, but above that of a typical AAA team, which is why players who could mash in AAA but couldn't hang on in the majors usually end up in the land of the rising sun. (Guys like Álex Guerrero and Casey McGehee were among the best hitters in the NPB in 2017.)
The NPB's style of baseball, however, is unique. It exists as some strange mesh of dead-ball play and modern baseball, where ground ball machines can thrive.
Earlier this year, Ben Lindbergh took a look at the biggest ground-ball-machine in the world, Nippon-Ham Fighter Takuya Nakashima, who ran an astonishing 74.4 percent GB% in 2016. Nakashima's batted ball profile looks like something of a caricature of the rest of the league, a gross exaggeration of the way the rest of the league plays.
Leaguewide, the NPB GB% year to year falls between 47 and 48 percent, which is quite a bit more than the 44 to 45 percent that the MLB posts every season. Japanese players traditionally reach base more frequently on grounders too, posting a BABIP of .245 on ground balls in 2017, compared to the MLB's .241 figure.
But, the biggest difference between MLB and NPB grounders? Ground balls are generally worth 30 percent more in Japan as they are in North America. MLB batters posted a 29 wRC+ on grounders, but NPB grounders were worth 42 wRC+. That's a huge difference, especially for a league-wide figure. While it's still not technically beneficial to hit groundballs, in Japan, hitters are rewarded for doing so more frequently than their North American counterparts.
How does such a huge difference exist between NPB and the MLB? Lindbergh, in the above article, suggests that the spongy Japanese turf is to blame, causing ground balls to have more life on them. In addition, Lindbergh suggests that the NPB, which has been slow to adopt many sabermetric and modern ideas, is shift averse, meaning many pull-happy hitters can run higher BABIPs. It's also possible that since NPB has a lower skill level than the MLB, NPB infield defense could allow more hits than MLB infields.
Whatever the reason, hitters who came to the MLB from the NPB while relying on the ground ball as a means of production generally saw their production suffer. Tsuyoshi Nishioka, for example, hit .346/.423/.482 the season before coming to the MLB, but managed only a paltry .215/.267/.236 with the Twins in two seasons. Nishioka relied heavily upon the ground ball in both leagues, but was punished more heavily for doing so in the MLB than in the NPB. That, coupled with the difficulty of facing MLB pitchers, doomed him to mediocrity.
Ichiro was similar—a ground-ball production machine. When he came over from Japan, perhaps in hindsight, he should have flopped for the same reasons that Nishioka, Kensuke Tanaka, Munenori Kawasaki, and Akinori Iwamura flopped. He fit the profile—speedy, high contact ground ball hitter coming over from Japan. Hell, Ichiro's best case scenario should have been what Nori Aoki turned out to be.
Instead, he thrived.
Ichiro Breaks the Mold
When Ichiro arrived in America, he was nothing short of a revelation. He was a key factor in the Seattle Mariners posting the best record of the modern era in 2001 and was arguably the face of the franchise for close to a decade.
Ichiro's high contact, low walk/strikeout approach shouldn't have worked. I ran Ichiro's 2003 season through my similarity tool, and the best comps I generated were Jose Vizcaino's 2004 season, Warren Morris' 2003 season, and Brad Ausmus's 2004 season (yes, that Brad Ausmus). None of these guys posted a wRC+ over 90 in those years, but Ichiro was at 112. How did Ichiro get by using a strategy that had failed so many hitters before him?
On paper, the answer is BABIP. For his first four seasons, Ichiro never posted a BABIP below .333. While the league average for BABIP is around .300, elite players generally have a BABIP skill above .300 as a result of making elite contact. If we make a rough and naive assumption that a high SLG means that a player made good contact, we see that among the top 15 career BABIP leaders (with 10000 PA), most of them made good contact, except for Lou Brock... and Ichiro.
It gets weirder. Remember all that talk about ground balls? Ichiro hit a lot of them—since 2002, the earliest season for which we have batted ball data, Ichiro has hit the most ground balls in the majors, almost 800 more than second place (Derek Jeter). Here is a scatterplot of GB% versus BABIP for qualified single seasons since 2002.
There is a weak, but roughly positive correlation between BABIP and GB%. Most everyone is hanging out somewhere around the 35 to 50 percent GB% and .250-.350 range, but then there's Ichiro, who consistently posts BABIPs well above what he should be getting. Ready? It gets even weirder.
Here's that same chart, but I've thrown in the ages of each hitter in a gradient color scale. There's a good spread around here, but I've highlighted Ichiro's 2004 season, and it should stand out in three big ways. First, he posted one of the highest GB% since 2002 (63.1 percent). Second, he posted the second highest single-season BABIP since 2002 (.399). And third, he was 30 when he did this! Many of the light blue values in the upper right of the column belong to Ichiro. Which is really unusual, since many of them are when he's older than the median MLB player (29 years old).
In this chart, the red dots represent hitters 29 years old or younger, and the blue dots represent hitters 30 years old or older. Notice how there's a roughly even mix in the middle, but older hitters tend toward the bottom left, and younger hitters tend toward the upper right (though there are exceptions to each).
Here's that same chart, but I've removed Ichiro's seasons—look at the far upper right. See the difference?
Ichiro's specialty is defying all aging curves and all logic by consistently posting these ridiculous BABIPs while acting like a groundball machine, and making contact that most hitters would be ashamed of.
Legs, Don't Fail Me Now
We've already established that Ichiro makes subpar contact, hits a lot of ground balls (not exactly a recipe for production), and doesn't strike out or walk much. No, Ichiro's biggest tool, as anyone who watched him play could tell you, was his speed.
August Fagerstrom previously found that Ichiro had elite speed in his younger days, estimating his time-to-first in his prime as just under 3.75 seconds, which would blow Billy Hamilton (3.95 seconds) out of the water. It's no exaggeration to say that Ichiro could be one of the fastest men in MLB history.
So many hitters came over from Japan with profiles similar to Ichiro—speedy groundball hitters who make a lot of contact. But none of them had Ichiro's generational speed, and so, none of them found the type of sustained success that he did.
One cannot help but feel a sense of wonder when looking at Ichiro's career. Because his production relies almost solely on his ability to make contact and his speed, tools that decay slowly with age (I'm aware that speed tends to decrease with age, but exceptionally speedy runners such as Chase Utley and Rajai Davis can retain their prowess on the basepaths well into their late 30s), he was able to defy what we might expect from someone of his age and with his batted ball profile.
Ichiro was shooting the moon with his approach to the plate, in a way. Sabermetric wisdom tells hitters to elevate, draw walks, don't be afraid to strike out, make solid contact, and don't worry about speed. Ichiro did the exact opposite and was handsomely rewarded for it. I can think of no more unique player with such a storied career and legacy. Here's hoping 2017 won't be Ichiro's last hurrah.