4-4 point Josekis
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4-4 Point Joseki are standard sequences of moves played around the 4-4 point that result in a locally even exchange. Joseki related to this position can be classified into approaches, invasions, enclosures, attachments, and extensions.
The 4-4 point (aka hoshi or 'star point') emphasizes influence, speed, and flexibility. Compared with the 3-4 point or 3-3 point, the corner can still be invaded and the territory is not secure. In modern go, it is one of the most popular openings (~60% frequency) and preferred by strong AI programs like AlphaGo.
Popular joseki related to the 4-4 point have evolved over the centuries. Some of the patterns listed in this reference are no longer considered "joseki", but the viability of unusual moves is highly sensitive to the surrounding board position. The difference in winning rate between traditional and modern joseki is often less than a point, so many old joseki are still valid and playable particularly at the amateur level.
|Table of contents|
Moves are listed by frequency in professional games, which is sensitive to whole-board position. Bolded moves are commonly considered joseki.
- a, 4-4 Point Low Approach - (joseki) (AI favorite) (common)
- b, 4-4 Point Direct 3-3 Invasion - (joseki) (AI favorite) (common)
- h, 4-4 Point High Approach - (joseki)
- i, 4-4 Point Large Knight Approach - (joseki)
- j, 4-4 Point Two-Space High Approach - (joseki)
- k, 4-4 Point 3-4 Attachment - (joseki)
- c, 4-4 Point 5-Space Low Splitting Move - (common) (splitting move) (wall extension)
- d, 4-4 Point 5-Space High Splitting Move - (common) (splitting move) (wall extension)
- e, 4-4 Point 4-Space Low Splitting Move - (common) (splitting move) (wall extension)
- f, 4-4 Point 4-Space High Approach - (wall extension)
- g, 4-4 Point 3-Space Low Approach (situational) (wall extension)
- l, 4-4 Point 3-Space High Approach - (rare) (situational) (wall extension)
- m, 4-4 Point 4-5 Attachment - (rare) (ladder breaker)
- n, 4-4 Point 2-5 Approach - (situational) (invasion)
- o, 4-4 Point 2-4 Approach - (situational) (invasion)
- p, 4-4 Point 5-7 Approach - (rare) (black hole fuseki?)
- q, 4-4 Point 5-5 Shoulder Hit - (rare/mistake)
- r, 4-4 Point 3-5 Armpit Hit - (rare/mistake)
- s, 4-4 Point 2-2 Invasion - (trick play)
- a, 4-4 Point Small Knight Enclosure - (joseki) (AI favorite) (common)
- b, 4-4 Point Large Knight Enclosure - (joseki) (common)
- c, 4-4 Point 5-Space High Extension
- d, 4-4 Point 5-Space Low Extension
- e, 4-4 Point 4-Space Low Extension
- f, 4-4 Point 4-Space High Extension
- g, 4-4 Point One-Space High Enclosure - (joseki)
- h, 4-4 Point Two-Space High Enclosure - (joseki)
- j, 4-4 Point Diagonal Enclosure - (situational)
- k, 4-4 Point Iron Pillar Enclosure - (situational)
- l, 4-4 Point 3-3 Enclosure - (rare/mistake)
Small knight approach
Large knight approach
Two-space high approach
- Among human players, the small knight's approach is currently the most popular move among professionals and amateurs, and it is well-regarded by AI. The small knight's move emphases a flexible balance of territory and influence. It threatens to enter the corner or extend along the side.
- The large knight's move is sometimes played to discourage a pincer, but it has a weaker follow-up on the corner.
- The high approaches emphasize influence or light play, but they are a local loss for for White in the early opening.
Invasion and Attachment Joseki
- The 3-3 invasion emphasizes solid territory in exchange for a significant loss of influence. Traditionally, it was considered an ill-advised move in the opening, but ever since the AI era, the opening 3-3 invasion has risen strongly in popularity.
- The 3-4 attachment is often less good than the 3-3 invasion, but it allows White to choose the direction of play. It can be utilized when Black has an existing position along one side.
- The second line approaches are not considered joseki unless Black has an enclosure or is already strong in the local area, in which case they are typically invasion strategies in the middle game.
Small knight enclosure
Large knight enclosure
Distant high enclosure
- The small knight enclosure is territorial, prevents White from approaching in a certain direction, and partially protects the corner from a 3-3 invasion. Attempts to invade this enclosure can locally result in a ko. The small knight's move is well-regarded by professionals and strong AI programs.
- The large knight enclosure emphasizes influence. White can still invade and live at the 3-3 point with a costly loss of influence.
- The other high enclosures are played less frequently, as White can still perform a 3-3 invasion, and Black's enclosure stone can seem misplaced by tewari analysis.
- The kosumi enclosure and iron pillar enclosure remove the possibility of a 3-3 invasion, but the moves are slow and not considered joseki during the opening. These moves are more commonly played in the middle game to remove aji or the threat of invasions.
Ever since the AI revolution (c. 2016), the 3-3 invasion has dramatically increased in popularity since it is often a preferred move by strong AI programs. The 3-3 invasion trades influence for territory, and it can be a good move for players with a territorial playing style.
Traditional dogma prior to the AI era was that the early 3-3 invasion was bad for the invader, because the loss in influence is not worth the limited territorial value of the corner. This notion may still be true for weaker kyu players who have not developed strong reduction, invasion, and fighting skills. Beginners should be wary of blindly invading corners without considering the overall board position and knowing the subtle differences in 3-3 joseki recommended by AI.
- All About 33 Point Invasion
- Black should resign if one player has four corners
- Kokiri's Introduction to the 3-3 Invasion (2010)
- Youtube (dwyrin 5d): Going Into the 3-3 (2021)
Further Reading: Leela Zero's opening gospel
Strong AI programs tend to assign similar value to approaching and enclosing symmetrical corners. Approaching corners is typically more popular among most players, but it is mainly a matter of playing style and personal preference.
See main article: Approach On the Open Side
Under traditional opening theory, approach moves should be played from the widest side. For example, in the sanrensei fuseki, attempting to play the knight's approach from inside the formation is like jumping into a loose pincer, and it will often result in a cramped weak group.
Similarly, enclosures should be played to prevent approaches from the widest side.
See article: Extension From a Wall
In modern go theory, extensions from thick and established walls should be aggressive and placed further than the conservative placement recommended by the traditional 'four-space extension from a three-stone-wall' go proverb.
These aggressive extensions are one reason why loose corner approaches are made by professional players. Although the distant approach may result in a local loss in the corner, the wide extension threatens to develop even more territory along the side.
In the following example, strong AI programs evaluate the marked letters as reasonable Black extensions from a popular 3-3 invasion. Notably, the conservative four-space extension recommended by the go proverb (marked with a square) is a candidate move, but it is inferior compared to the other options, slightly overconcentrated, and not ideal for this board position.
See article: Splitting Move
Third-line splitting moves near the side hoshi (hoshishita) are a common and traditional way to develop a base along the side. Playing off-center, particularly on the hoshiwaki can be advised depending on global board position.
See individual enclosure pages for detailed joseki.
- Nirensei Fuseki
- Sanrensei Fuseki
- Orthodox Fuseki
- Mark II Kobayashi formation
- Handicap Go
- Yonrensei Fuseki / Gorensei Fuseki / Kyurensei Fuseki
- Pseudo-Kobayashi Fuseki
The first experiments with the star point were around 1840 in Japan; its first appearances in pro games date to the early 1900's. Its rise to preeminence came during the 'New Fuseki' movement in Japan in the mid-1930's.
-  Frequency statistics were obtained from Waltheri's Go Pattern Search using the full database restrained to a local search (accessed August 2021). Due to the weighting of older games in the database, the 3-3 invasion appears to be less frequent than it actually is in recent years. With the search restricted to contemporary/post-AI games, 20-30% of 4-4 approaches are 3-3 invasions.
-  AI score estimates were obtained from katrain (v1.9.3) using a Nirensei board with two star points occupied by each player. AI score estimates can vary widely depending on the board position and software version, and should be taken with a grain of salt. Notably, the point values of many joseki on this page differ by less than a one point, indicating that many of the listed joseki are indeed playable at all levels.
-  Kogo's Joseki Dictionary