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. The second kind became interesting only after the introduction of komidashi. Go opening strategy is the strategy applied in Go opening. There are some conventional divisions that are applied. Firstly there is the distinction that may be drawn between go opening theory, the codified variations that resemble chess openings in the way that they occur repeated in games, and go opening principles. Since there is great freedom of choice, the fundamental opening principles are more useful for all players before they reach dan player level. Basic principles Examples of principles that are generally useful are comments such as 'corner-side-centre', which says that the corner areas of the board are more valuable than the sides (points near an edge but away from the corners). Occupying points in the centre may be good for early fighting, but these points are weaker from the aspect of developing one's territory. Developments over the last century The opening strategy in Go can be said to have undergone some major changes in the twentieth century. Not only have new joseki been developed, but some important shifts in thinking have occurred. For example: from 1900 to 1930 the strategy was traditional, the so-called Shusaku style in 1933 and for a few years afterwards, a very different and experimental style called shinfuseki dominated professional go, at least for the younger players from around 1936 there was a compromise of styles, sugou fuseki, which mixed some of the more successful ideas from shinfuseki with older techniques for a more balanced approach, forming the basis of modern professional play the introduction of komidashi of 4.5 points in most top tournaments of the 1950s led to a tighter, territorial style for Black, for example in Sakata Eio, with greater use of the 3-3 point for White also. the Chinese opening dominated thinking from the early 1970s, and many further ideas were tried, for example the mini-chinese formation which is a side opening, rather than a corner opening or whole-board opening the entry of South Korean professionals into international competitions