Panama to South Korea

[Goulash]

I'm interested in your opinions on the Fastest (while still being safe) passage from Panama to South Korea.

I know the highway basically goes Panama via the Southern Pacific, through the Pacific Islands then, if heading to SE.Asia, turns north somewhere around the Marshals (unless going all the way across to Oz and then north) but is there a fairly common, more Northern route? Heading up the West coast of America then across perhaps?

I'm finding it difficult to find any info about the lesser traveled East Asia (North of Philippines.)

[Benz]

Have you looked at Hawaii--Midway--Japan--ish? Lots of open ocean, but a close consultation of the pilot charts and Jimmy Cornell's "World Cruising Routes" might shed some light on it.
I'm guessing even if it's feasible, it's not common.

[Dsanduril]

Welcome to the forum Goulash.

I'm with Benz, if the purpose is getting from A to B I'd look at Panama-Hawaii-Midway (actually probably Ogasawara)-Japan. I've done the Panama-Hawaii leg (that is a looong passage) and the Hawaii-Midway leg. If you hold the latitude of Hawaii/Midway you should be able to create a downwind/reaching passage most of the way, with E and NE trades veering to SE and S as you approach Asia. I'd have to study the last third, but the first two-thirds are pretty straightforward as passagemaking goes, point the boat and go.

If the question is about timing, well, it's probably too late for this year and a swing through the south would probably be a better approach. The monsoon looks like it has set in in Panama, it usually does sometime in April. That leaves you with contrary and usually very light winds for the first 1000 to 2000 miles before your reach the trades. Leave in late February/March/early April and you can frequently avoid that light and fluky patch.

Now also puts you at the start of the North Pacific hurricane season, and that first 2000 miles parallels the Central American coast where the early season storms like to form. Hawaii is usually later season storms, but being stuck in a light wind situation with no way to run and right in the middle of the early-season formation area wouldn't be my first choice.

It's a tad over 8000 miles Balboa to Kyushu with Hawaii close to the middle. Winging it a bit, I'd probably shoot for late February/early March departure, to arrive Hawaii early April. Not long there, then Ogasawara by late May. From there you can wait on the weather and either go to southern Kyushu or straight to Korea.

That's the short version, there's a lot of details to be worked out in all of that. You're sailing across a largely empty portion of the ocean, there simply aren't a lot of places to stop. I don't mind that (I thrive on long passages) but they aren't everyone's cup of tea.