These do not necessarily apply in China or Korea, but naturally in speaking of an 'opening' one never needs to distinguish openings related by symmetry.
It may lead to what is called mirror go, in Japanese manego, in which Black imitates White by playing diagonally opposite with respect to the centre stone.
There is another style, also called mirror go, where from the beginning of the game White imitates Black in a diagonally-opposite way.
The first kind was interesting, for strong players, before the introduction of komidashi, i.e. compensation points for second play.
More accurately, it means the 'scattering' or thin distribution of stones that occurs in the early part of the game.
Since White has a choice of perhaps two dozen legitimate variations on the other side, these are in fact large complexes of openings.
If Black and White both play the joseki correctly, they should achieve a balanced result within that particular corner; neither should have a large advantage, unless the opponent makes a mistake.
[7] "Balance" typically refers to an equitable trade-off between securing territory in the corner versus making good thickness toward the sides and center.
The assessment also takes into account who started and ended the corner sequence: if Black has played one more stone than White in the corner, for example, Black's result should be objectively better than White's, to reflect the extra investment of a play.
In application these concepts are in fact very dynamic, and often joseki are deviated from depending on the needs of the situation, and the opportunities available.
Usually joseki as a term (in literature in English) is applied to a set sequence happening in one corner in the opening stage.
[8] The current body made up of joseki is not fixed, but consists of patterns that have gained acceptance in professional games.
Hence the basic definition may be misleading for new players in that joseki can be misconstrued as foolproof and unalterable, and are otherwise optimal for all situations.
Hence the study of joseki is regarded as a double-edged sword and useful only if learned not by rote but rather by understanding the principles behind each move.
Just as using an improper tool in machinery can be devastating, choosing the wrong joseki can easily be worse than improvising one's own moves.
Rui Naiwei similarly remarked that playing joseki is easy [but] choosing the right one [in a game] is hard.(par.)
Opening theory is less dominant in terms of study for those wanting to reach a good amateur level, than in chess or shogi.
Go Seigen played his third move (Black 5) on tengen, in a 1933 game against Honinbo Shusai, the top player of the time.
Go lost the controversial four-month game, which was played over 14 sessions in a ryokan in Tokyo from 16 October 1933 to 19 January 1934.