囲碁 発陽論/ 围棋 发阳论/ 圍棋 发阳论/ 위기발양론/ Igo Hatsuyoron
Problem 120 – Interactive Solution with WGo

Here, we discuss a single problem (#120) from 囲碁 発陽論 (Igo Hatsuyōron) – in Chinese: 围棋 [圍棋] 发阳论 (Wéiqí FāYángLùn), and in Korean: 위기발양론 (Wiki Balyangron) – attributed to 井上道節因碩 (Inoue Dosetsu Inseki, 1646-1719)

This page is a supplement to the extensive web-site about this classic problem, maintained by Thomas Redecker. Sensei's Library has more links to further analyses of this problem.

Please Note: the main web site has very detailed comments. The file used here has almost no comments, and shows the latest (at mid 2017) substantive research, which is still going on.

You can download the SGF file of the game record that we use below.

Problem 120 – view & edit

N.B. The interactive board uses Javascript. Please make sure that you have enabled this in you browser.

Using EidoGo to View, Edit, and Explore

To move around game record:

There are several methods.

• Use the arrow keys in the viewer, or on the keyboard.
• Use the red slider – move number is shown just above at right.
• Select a variation: either click on the board – numbers in orange squares; or click on red numbers, in pale squares near top of pane at right. With care, you can also use the Game-Tree at the right, below the board – see below.
• Select a move using the Game-Tree: it is displayed at bottom right – numbered B & W stones. The current node is displayed as a red square in the Game-Tree.
• Select Tool: → Jump to Move, and then click on the point (empty, or occupied!). You will then jump to the first occurrence of that move, in the earliest (subsequent) variation in the game record.

To change the game record – e.g. try new variations:

• With "Tool Play" selected at right, click on an empty board point to add a move to the end of a variation, or to start a new variation.
  It seems that you cannot permanently add moves in the middle of a variation, or game-record. They have to be added as stones, instead.
  Sometimes, if you are lazy, you may want to do this if you have forgotten to include an exchange earlier in a sequence, and now want to check the possibilities as if you had played the exchange earlier!
• Remove Black/White stones, or variations – DANGEROUS: Use Tools Black/ White stone, then click on an existing stone.
  • If the stone is the current move, then you will be warned "You've removed all properties from this position. Delete this position, and all sub-positions? [ OK ] [ Cancel ]". Beware – answering "OK" will remove all the rest of that branch/variation, including all sub-trees/sub-variations from then onwards.
  • If the stone is not the current move then the deleted move/stone will no longer be displayed when the current move is current again. However, it is still in the game-record, and will appear, as usual, at all other points in the game record. Confusing!
  It seems that you cannot permanently remove moves in the middle of a variation, or game-record. However, you can remove the stones. Sometimes, if you are lazy, you may want to do this if you have played an exchange earlier in a sequence, and now want to check the possibilities as if you had not played the exchange earlier!
  To mimic deletion of moves, the work-around is to do Tools: Black Stone, and Tools: White Stone, at the correct point in the game-record – these will not count as moves in the sequence, but will be displayed as stones at all points after this in the game-tree! :-)
• Add marks/labels – Tool: triangle, square, cross, number [autoincrement], or letter [autoincrement].
• Lowlight areas with "Tools: Dim" – helpful with comments
• Clear marks/labels, or "Dim": Tools: Clear Marker
• Add Black/White stones – use Tools: Black/ White Stone, and click on point.
• Apparently, cannot add comments with this tool, on this page.

Currently, we do not offer you the option to download the modified SGF file to your computer.

This page is powered by EidoGo – a Go client, and editor (and much more), easily included in web pages. Download your own version, or check out the notes on EidoGo at Sensei's Library.