Jin-Sung Kang is a Two-Strike Genius

Written by: Justin Choi (@justinochoi)

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Listen up Roberto Ramos, Jose Miguel Fernandez, and Mel Rojas Jr. – your foreign oligopoly on KBO hitting is over.

Why? Because Jing-sung Kang (강진성) of the NC Dinos has arrived. After a modest start to the season, the first baseman is slashing .450/.500/.810 as of June 15th, which adds up to a monstrous 234 wRC+. His sneaky ascent has taken many – including myself – by surprise, which is why in this article, I’d like to talk a bit about him. 

All great hitters have idiosyncrasies. Barry Bonds got on base, even in games where he went hitless. Ichiro slapped a ton of infield singles. George Springer showed off his clutchness by hitting five home runs in the 2017 World Series. Jing-sung Kang’s idiosyncrasy, in contrast, is subtle: he is unstoppable during two-strike counts. 

Normally, two-strike counts are the bane of every hitter’s existence, as an additional strike equals an out. Escaping them takes considerable effort. It’s an uphill battle that requires to carefully take pitches or foul them back, but one mistake and it’s all over. The MLB-average wOBA on two-strike counts in 2019 was .237, nearly 90 points lower than the overall league-average of .320. With a .340 wOBA on two strikes last year, even Mike Trout was reduced to a mere mortal. 

For Jin-sung Kang, however, this isn’t a problem. In fact, you could say that he thrives in dangerous situations  – just look at his triple slash on various two-strike counts (wOBA on specific counts are not available on Statiz, so I’ll have to make-do with traditional stats): 

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Across a 60 PA sample of two-strike counts, Kang is producing at an elite level. But wait, aren’t great hitters productive in any situation? For example, as Ben Clemens once pointed out, the difference in wOBA between an 1-0 and 0-1 count (93 points) is far greater than the difference in the average wOBA of hitters who reached 1-0 and 0-1 counts (5 points), giving weight to the argument that the value of being ahead is inflated by the Mike Trouts of the world. 

Although he ultimately concluded that count is still king – with which I agree – I nevertheless decided to compare Kang’s performance on 0-2 counts with that of his contemporaries. Why an 0-2 count? Because almost every hitter becomes terrible in one. If Kang is truly the outlier I claim he is, the difference should show in the most polarizing situation: no balls, two strikes. 

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In 0-2 counts, Jose Miguel Fernandez and Mel Rojas Jr. are like 99% of hitters: chumps. But Roberto Ramos, once again showing off his brilliance, is doing even better than Kang! Does this mean that his two-strike dominance isn’t unique? Don’t forget, however, that we haven’t examined other two-strikes counts yet, and to decide a winner between Kang and Ramos, I did just that, using OPS to simplify the table: 

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Sure, Ramos has the edge in 3-2 counts, but overall it’s safe to say that Kang is on top when it comes to two-strike hitting. There’s nobody like him in the KBO, and certainly nobody like him in the MLB. What makes this distinction truly amazing, however, is that Jin-sung Kang one or two years ago was nowhere near the hitter he is now. This year, he’s struck out 12 times and recorded a 225 wRC+ across 110 PAs; in 2019, he struck out 20 times while recording a 84 wRC+ across 104 PAs. The difference is not just night and day – it’s black hole and supernova, the luminous explosion of a star that’s a metaphor for Kang’s breakout. 

How did Kang improve? There are a few to note, like hitting balls to the outfield 62.7% of the time, or lowering his SwStr% from 12.2% to 10.9%, but staying on- topic, here’s a table showing a two-strike-related change: 

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What’s funny is little evidence suggests that an increase in two-strike swing% benefits a hitter. According to Savant, there is near-zero correlation (r^2 = 0.02) between it and wOBA. MLB hitters in 2019 who swung as often as or more frequently than Kang did in two-strike counts (min. 50 BBE) include: Kenta Maeda and Nico Hoerner. Yeah, not a list you want to be on. 

So the question is, why does swinging 83.8% of the time work for Jin-sung Kang? The answer is, well, I don’t know! It’s as baffling as his ability to produce in two-strike counts. My hunch is that the two are interdependent – that is, Kang is so confident in his swing that he can get away with his idiosyncratic approach. KBO batted ball data is not available to the public, but there must have been some increase in exit velocity, launch angle, or both that helps Kang barrel balls at an insane rate. 

Ultimately, the purpose of this article is not to pinpoint why Jin-sung Kang is breaking out, but rather to emphasize that behind every breakout is a baseball quirk worth analyzing. For Jin-sung Kang, it’s the ability to consistently win the two-strike battle. I have no idea whether or not this victory streak is sustainable, but as long as he’s having success, I am here to enjoy it. 

Follow P365 KBO Analyst Justin Choi on Twitter! @justinochoi

Follow us on Twitter! @Prospects365

(All statistics are from Baseball Savant, Fangraphs, and Statiz)

Featured image courtesy of Yanhap News and the respective photographer


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