Condense edited position in game tree

Hello, I posted about this in 2016 before there was a feature suggestion section in the forum but I would like OGS to display edited moves in the game tree differently. Currently OGS displays edited moves in the same way as regular moves. If you edit in multiple stones, each edited stone will show up as an individual move in the game tree. This makes it so if you make large edits to the board position or set up a problem on the board, it shows up as a long string of individual moves. This then makes it extremely confusing to navigate the game tree. Other programs will often condense all of these edits into a single icon on the game tree which greatly helps with tree navigation.

Example of the same SGF file in OGS vs CGoban:



This already seems to be a distinction supported in the SGF file format. “;W” and “;B” are for white and black moves whereas “;AW” and “;AB” are used when a move is edited in. OGS seems to just not make this distinction and treat both as a move when displaying in the game tree.

Example of these different notations.


I like this idea.

Some questions/thoughts:

  • Should all consecutive edits that lack intervening moves be collapsed? Or does there need to be a facility to separate adjacent edit-groups somehow? (The former sounds easier to implement and reason about… just not sure what you’re intending / what other tools support…)
  • Have you thought about what the icon should be in the game tree for an “edit node”? (which can include both white and black edits)
  • It might be nice to use this icon for all edits, even if it’s just a single edit, so we can distinguish visually between a “move node” and an “edit node” in the game tree.
  1. Yes, how it usually works is all edits for both colors are condensed down into a single icon. Then when a normal move is played (either a move on the board or a pass), a new icon is then created with any further edits.

CGoban example:


2)The first icon that comes to mind would be a stone that’s half each color. With the power of my amazing MS paint skills… something like this?

edit: or i guess OGS already uses this for the edit button so just use the same icon in the tree.

  1. Yes I agree
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What do these two consecutive triangles represent (circled in green):

If those are separate edit-groups, then how does the interface enable those to be created? (EDIT: For example, why are they not collapsed into one?)


Those were created by passing instead of playing a move in between edits.

Edit 1: Looking at it farther. CGoban seems to make a distinction between passing while in move mode vs edit mode. When I pass in move mode it creates a move icon but when I pass in edit mode it doesn’t switch which players turn it is and creates an “empty” node.

Edit 2: How this seems to be represented in SGF file format is a pass is ;W[ ] or ;B[ ]. but an edit mode pass is just a " ; " with nothing following.
Red = regular pass, Blue = Edit mode passes

Edit 3: So It seems which players move it is only toggles with a " ;W " or " ;B " but a new game tree node is created with just the presence of a " ; ". This seems true with edits also. All of the edits appear in the same node and are all listed with a single leading " ; ".

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but when I pass in edit mode it doesn’t switch which players turn it is and creates an “empty” node.

It makes sense that you can’t pass in edit mode, since you can’t make other moves either. But this interaction seems a bit subtle. It’d be more clear, I think, to rename the “pass” button to “new node” (or something) when in edit mode.

yes, it seems the key is " ; " creates a new node in a tree. The AW and AB, along with AE (add empty, for when stones get edited out), properties are all located inside a single " ; "

(in the example it’s 2 nodes since ;AE is removing the stones added in the previous node)

I had a quick look, and this isn’t straightforward to implement. The goban model currently only supports one edit per node, so that would need to be fixed first.

I filed two issues to track this:

My first impression is that the goban piece is not a small project, but I think it’s tractable.


Alright, thanks for taking a look. I’ll keep my eyes out for any progress on those issues.