Last time, we looked at the top ten hitting seasons of the 2020s in Nippon Professional Baseball. This time, we flip over to the pitchers. Batting can be analyzed pretty easily by viewing production through OPS+ or wRC+. Players can overperform or underperform their expected numbers due to batted ball luck, but things typically start stabilizing over the course of a long season. Production is production, regardless of the situation.

The same can’t be said for pitching. Yes, all pitchers are in the business of run prevention, but ERA alone doesn’t tell the whole story because it’s somewhat situational. A pitcher could load the bases every inning and still have a scoreless outing, depending on the sequence of hits and walks he allows. Thus, stats like FIP — which solely looks at a pitcher’s strikeouts, walks, and home runs — and kwERA — which further isolates skills to just strikeouts and walks — are useful tools to evaluate true pitching ability.

Of course, some would still argue that ERA is king because it literally measures “what actually happened” as opposed to “what should have happened.” There are arguments in favor of both sides. With that in mind, here are the top ten qualified seasons by ERA+, FIP-, and kwERA- since 2020:

100 always represents league-average. Higher values are better for ERA+ while lower values are better for FIP- and kwERA-. Technically, an ERA+ of 125 would indicate the league-average is 25% worse than the player, whereas a FIP- or kwERA- of 75 would indicate the player is 25% better than average. These metrics allow us to compare different run environments, which is particularly important since NPB has used a dead ball since 2022.

Yoshinobu Yamamoto’s dominance is staggering. He owns each of the top four seasons this decade by FIP-. He won the MVP, Triple Crown, and Sawamura Award in back-to-back-to-back years from 2021 to 2023. Except for his friend Hiroto Takahashi (currently a 1.14 ERA, 241 ERA+), nobody has even approached his peak ERA+. With impeccable command, a fastball in the mid to high-90s, and two elite secondaries in the curveball and splitter, the Orix Buffaloes ace finished his NPB career with a 1.82 ERA across nearly 900 innings. His 1.21 ERA in 2023 was the fourth-lowest in NPB history. He had a 1.76 FIP thanks to a very healthy 169:28 strikeout-to-walk ratio and just two long balls allowed in 164.0 innings. The Los Angeles Dodgers subsequently handed him a $325 million contract.

The 2020 season appears frequently on these leaderboards, partly because it was only 120 games due to the COVID-19 pandemic. Even the top workhorses only made around 20 starts that year, so it’s a smaller sample. Still, what Tomoyuki Sugano, Yudai Ohno, and Masato Morishita accomplished was incredibly impressive, and they were each rewarded accordingly.

Sugano was 14-2 with a 1.97 ERA, 2.91 FIP, and 19.9 K-BB%. He was named Central League MVP. The Yomiuri Giants future Hall of Famer was also a strong candidate to take home his third Sawamura Award (Japan’s Cy Young equivalent), but Ohno edged him out with an 11-6 record, 1.82 ERA, 2.97 FIP, and 22.4 K-BB%. What pushed the Chunichi Dragons southpaw over the top was an NPB-leading ten complete games and six shutouts. Morishita won the Central League Rookie of the Year Award with a 10-3 record, 1.91 ERA, 2.86 FIP, and 19.0 K-BB%, propelling the Hiroshima Carp right-hander to be the co-ace of Samurai Japan at the Olympics alongside Yamamoto.

Speaking of rookies, Shoki Murakami shocked the nation with a masterclass in command en route to the 2023 Central League ROY and MVP. Murakami perfectly mixed speeds as all five of his pitches had opponents batting under the Mendoza line. He had the third-lowest walk rate in NPB at 2.8% while striking out 25.8% of the batters he faced, leading the Hanshin Tigers to their first championship since 1985. The Yamamoto vs. Murakami Japan Series matchups were must-watch television, with the superstars picking up a win apiece.

Other standout arms on the lists include Kodai Senga and Shota Imanaga, who have had great success in their short time in Major League Baseball so far. Neither one had an extended period at the top of the NPB food chain like Yamamoto or Sugano but had impressed at the international level and were extreme stuff anomalies. Senga always embodied the “effectively wild” pitcher, with a career walk rate of almost 10% and injuries that led to some volatility. Yet, Senga’s mid to high-90s fastball and now-famous “ghost fork” induced exceptional ground ball and whiff rates, winning the SoftBank Hawks flamethrower the Triple Crown in 2020.

Similarly, Shota Imanaga’s “rising fastball” is a well-known weapon of the former DeNA BayStars southpaw. In his final NPB season, the “Pitching Philosopher” exhibited his strengths and weaknesses to the fullest extent, with an NPB-worst 2.9 HR% and an NPB-best 25.2 K-BB%. His extreme fly ball profile while throwing in the bandbox known as Yokohama Stadium led to an underwhelming 115 ERA+ but an astoundingly good 63 kwERA-.

The name everyone hoped to see on here is Roki Sasaki, but he’s yet to pitch a qualified season. We were robbed of greatness in 2023, as he missed two months with a torn oblique. In 91.0 frames, the Lotte Marines phenom had a 1.78 ERA (185 ERA+), 0.94 FIP (25 FIP-), and 1.38 kwERA (38 kwERA-) while averaging over 99 mph on his heater. He was special.

Whether you prefer to evaluate players traditionally or sabermetrically, it’s worthwhile to have several different lenses to recognize greatness. Japan is full of pitching talent, whether they take the stage in NPB or MLB.