2d jump

[Pippen]

Let's say you are just became 4d and you wanna try to jump to 6d. If you win 18 in a row, you jump, but do you also jump if you lose one game somewhere and win the rest?

[Kirby]

Let's say you are just became 4d and you wanna try to jump to 6d. If you win 18 in a row, you jump, but do you also jump if you lose one game somewhere and win the rest?

I assume the system is the same between Korean and English servers, so the page here should apply:
http://service.tygem.com/baduk/baduk_grade.html

The 1-4d category is listed as this:

단 (1단~ 4단) :
2단 상승 (승률 90%이상, 20국 기준 18승 2패 이상)
1단 상승 (승률 70%이상, 20국 기준 14승 6패 이상)
1단 강단 (승률 30%이하, 20국 기준 6승 14패 이하)
2단 강단 (승률 10%이하, 20국 기준 2승 18패 이하)

So to jump up two levels, you should have win rate of 90% or higher for the set of 20 games (at least 18 wins and 2 losses).

It changes for levels between 5d and 9d:

단 (5단 ~ 9단) :
2단 상승 (승률 100%, 20국 기준 20승 무패)
1단 상승 (승률 75%이상, 20국 기준 15승 5패 이상)
1단 강단 (승률 35%이하, 20국 기준 7승 13패 이하)
2단 강단 (승률 15%이하, 20국 기준 3승 17패 이하)

After you're 5d, you need to win 100% of the 20 game set without any losses to jump up two ranks.

[Kirby]

I guess I didn't answer your question directly. Yes, you'll still go up if you only lose 1 game in the last 20 game set.

An example for 4d is given on the page I linked:

4단님의 최근 20국 OOOOOXOOOOOOOOOOXOOO (18승 2패) - 2단 상승

That is, supposing the 4d's most recent 20 game set has this record (O = win; X = loss):
OOOOOXOOOOOOOOOOXOOO

Then he has 90% win record, so he jumps up two levels to 6d.

[Pippen]

Thx, kirby.