This is the third part of an observation of how NPB’s hitting populations are different from how they are in the majors.

After Tom Tango (@tangotiger) commented that the populations of left-handed and right-handed hitters in MLB are essentially the same when batting with the platoon advantage since 2011, I began looking at NPB that way, comparing performances only with the platoon advantage.

In the previous studies, I excluded foreign hitters, switch hitters and pitchers (sorry Shohei). To get a broader look at how MLB and NPB compare left to right, I’ve included everyone.

Big numbers

Org.	LHB+ PA	RHB+ PA	LHB+ Percentage
NPB	233,586	286,969	44.9
MLB	629,795	846,835	42.7

LHB+ includes switch hitters batting against RHP, while RHB+ includes switch hitters batting against LHP.

The table below show how similar MLB’s left- and right-handed hitting populations are with the platoon advantage since 2011. Right across the board, the slash lines for hitters with platoon advantages are about as close as you can get.

MLB LHB, RHB with platoon advantage, 2011-2018

	PA	AB	H	2B	3B	HR	BB	K	BA	OBP	SLG	OPS	HBP	SF
RHB+	286,427	256,019	66,606	13,737	1,196	8,316	24,652	56,712	.260	.328	.421	.748	1,923	1,856
LHB+	511,532	454,808	117,171	23,608	2,972	14,271	47,033	99,412	.258	.330	.417	.747	3,672	3,305

These numbers came from Baseball Reference.

While the home run frequency in NPB is significantly lower all around, it is particularly obvious among batters swinging from the left side of the plate. The isolated power (slugging average minus batting average) of RHBs and switch hitters vs LHP is .139. For LHBs and switch hitters vs RHP, the isolated power is .111.

NPB LHB, RHB with platoon advantage, 2011-2018

	PA	AB	H	2B	3B	HR	BB	K	BA	OBP	SLG	OPS	HBP	SF
RHB+	91,494	80,286	20,422	3,765	298	2,279	7,779	16,373	.254	.323	.394	.717	667	521
LHB+	177,531	156,917	40,997	6,792	980	2,868	14,934	30,842	.261	.329	.372	.700	1,281	968

Results of individual plate appearances by LHB and switch hitters vs RHP, and RHB and switch hitters vs LHB in NPB from 2011 to 2018

Playing the percentages

The following table shows how left-handed hitters with a platoon edge compare percentage-wise with right-handed hitters. The categories are: Singles, doubles, triples and home runs as a percentage of hits, strikeouts as a percentage of plate appearances, and at-bats per home run.

MLB percentages

MLB	1B pct	2B pct	3B pct	HR pct	K pct	HR rate
RHB+	.65	.21	.018	.125	.198	30.8
LHB+	.65	.20	.025	.122	.194	31.9

Percentage of total hits by: singles, doubles, triples, home runs. Strikeouts per PA. ABs per HR.

NPB percentages

NPB	1B pct	2B pct	3B pct	HR pct	K pct	HR rate
RHB+	.690	.184	.015	.112	.179	35.2
LHB+	.741	.166	.024	.070	.174	54.7

Percentage of total hits by: singles, doubles, triples, home runs. Strikeouts per PA. ABs per HR.