Tuesday 1 March 2011

Study of Navigation in Reviewing A Go Game

Use case 1

Id: UC01
Name: Level 0
Scenario: There is no variation at all. There are only comments, marks and labels.
Scope: Original or light commentary games
Commands required:
Basic navigation commands

  • Next move - NM
  • Previous move - PM
  • End of game - EG
  • Beginning of game - BG
  • Fast forward - FF
  • Fast rewind - FW
  • Go to arbitrary move - GM

Use case 2

Id: UC02
Name: Level 1
Scenario: There are variations on main path. There is no variation on variations.
Scope: Most commentary games
Commands required: Basic navigation commands plus following commands (Variation Commands):

  • Next variation - NV
  • Previous variation - PV
  • Back to nearest fork of variations- BF
  • Go to arbitrary variation - GV

Notes on command: Suppose the game tree looks like
A – B – C – D
––B’– C’– D’
––B”– C”–D”

  • NV can be applied from node {A, B, C, D} to node B’, or it can be applied from node {B’, C’, D’} to node B”;
  • PV can be applied from node {B”, C”, D”} to node B’, or it can be applied from node {B’, C’, D’} to node B;
  • BF can be applied from node {B, C, D, B’, C’, D’, B”, C”, D”} to node A

Use case 3

Id: UC03
Name: Level 2
Scenario: There are variations on variation.
Scope: Joseki(定式), death and live
Commands required: Basic navigation commands, Variation commands

Use case 4
Id
: UC04
Name: Level +
Scenario: There are comments that reference an arbitrary node in either main path or variations
Scope: Joseki or heavily commentary games
Commands required: Basic navigation commands, Variation commands and following Node referencing command

  • Go to arbitrary node – GN
  • Previous node – PN: It goes back to the node where a “Go to …” command executed.
  • Next node – NN: It is the opposite command of PN from the history of navigation point of view. It goes forward through navigation history.

Explain: Suppose the navigation history looks like
A – B – C, from oldest to newest

  • If we are currently at node B, NN takes us to node C and PN takes us to node A;
  • If we are current at node C, NN does nothing and PN takes us to node B;
  • If we are current at node A, NN takes us to node B and PN does nothing.