Surely Korea works sometime.
I mean, I already wondered if they would slow down during the holidays and was informed they do indeed have the same holiday tradition. So at some point, they've got to go back to work like the West, right?
Having worked with (and currently working with) businesses in Asia and elsewhere, they have many holidays we don't, and don't celebrate a number that we do. Fiscal quarters generally are based on a corporate work cycle, for example several companies here in the states I've worked with you'd consider "American" actually have a starting quarter in mid-summer, June or July and one I've worked with in August.
Several companies I work with overseas - never stopped for the eastern holiday season. I myself worked right through it in fact. Never assume much about overseas (or even stateside) businesses having a set of 'rules'. Most software based companies work based on product cycles, market share opportunities and so on. AAA game companies often start to ramp up for the holiday season in May or June, which puts their efforts for development in the February / March time frame, so budgeting might hit around October/November with ramp up in Dec/Jan. It really depends on the company. I've seen all kinds of schedules over the years. Depending on what their big delivery cycles are - that's where you want to look at, and then roll back from there.
If the company traditionally drops product say in October to account for NA holiday sales, that's one thing if they're focused on on line DLC deliveries over a set of scheduled drop dates with one two titles a year - they'll have a delivery train set up for development, so if that's the case look for their financial quarters based on their stock filings. (As a rule of thumb... like I said, there's no assurances.)