FIFI25 vs. murasawa, October 2021 - Revision history

Selinger: Added a link.

2022-08-28T23:16:19Z

Added a link.

Selinger: Capitalization

2022-07-26T02:13:08Z

Capitalization

Selinger: Some punctuation, capitalization, typo

2021-11-22T15:17:19Z

Some punctuation, capitalization, typo

Demer: added variations and explanation

2021-11-21T23:07:32Z

added variations and explanation

Show changes

Demer: added hexworld.org/board link

2021-11-15T06:39:37Z

added hexworld.org/board link

Demer: various improvements

2021-11-13T23:36:18Z

various improvements

Selinger: Added category and added table number to a link.

2021-11-13T19:38:00Z

Added category and added table number to a link.

Demer: /* Moves and Comments */ fixed typo

2021-11-13T09:52:13Z

‎Moves and Comments: fixed typo

Demer: Demer moved page FIFI25 vs. murasawa to FIFI25 vs. murasawa, October 2021: included date, to match other commented games

2021-11-13T09:38:26Z

Demer moved page FIFI25 vs. murasawa to FIFI25 vs. murasawa, October 2021: included date, to match other commented games

Demer: created page

2021-11-13T09:34:30Z

created page

New page

== Game information ==
* Size: 11x11
* Red: FIFI25
* Blue: murasawa
* Result: 1-0 (Red won)
* Comments: Eric Demer
* Location: [[Board Game Arena]], game [https://boardgamearena.com/table?table=212776246]

== Coordinate Conversion ==

This game was played with BGA's old hex implementation, so its coordinates and board orientation are different from what's shown on this page. I apply a small rotation to show move coordinates and positions on this page:

(11;11) -> a11 (1;11) -> a1 (1;1) -> k1 (11;1) -> k11

== Moves and Comments ==

FIFI25 plays 1. a11

murasawa does _not_ swap, and plays 2. f6

<hexboard size="11x11" contents="R 1:a11 B 2:f6"/>

----

3. e6 good This works with the swap piece, since normally play towards an obtuse corner would favor whoever is on the [[short diagonal]], but a11 means it would favor Red here.

4. e4

5. g7 h7 would normally be better ([[joseki]]), but g7 is good here, since if Blue connects to the k-edge with 6. h5 , then [[Peep|7. g5]] works well with f6, due to [[Edge_templates_everybody_should_know#Fifth_row_edge_templates_with_two_stones|the edge template that f5+g5 would form]].

6. f5

<hexboard size="11x11" contents="R a11 3:e6 5:g7 7:h5 9:c4 B f6 4:e4 6:f5 8:h4 10:c3"/>

7. h5 8. h4

9. c4 good ([[joseki]]) Blue is fairly strong towards the a-edge, so Blue will probably connect a-edge. That means Red will probably need to ladder along the 1-edge, and c4 will be quite helpful with such a ladder.

10. c3 [[joseki]] again

----

11. d3 12. c5 This ends the [[joseki]].

13. e5 This seemed fine to me until I saw Blue's response :-). Due to that response, Red should've tried j3 instead. (j3 would create a ladder along the 1-edge towards a1 and a ladder along the k-edge towards k11.)

14. e8 This wins for Blue, though Blue did _not_ keep the win: Due to c3, Blue can keep c5 connected _and_ serving as an escape for height-3 ladders (Red can't [[Foiling|foil]]), so Blue connects to the a-edge via f5 or c9. For the k-edge, h4 gives Blue either a height-2 ladder plus a [[Switchback#Switchback_threat|switchback threat]] or a height-3 ladder, and either of those is enough to [[Climbing|climb]] to e8.

15. j3

<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 1:d3 3:e5 5:j3 7:f4 9:b4 B f6 e4 f5 h4 c3 2:c5 4:e8 6:h3 8:j2 10:b3"/>

16. h3 This is locally good - Blue is being [[Tidiness|tidy]] before laddering along the k-edge - and keeps Blue's win, but was not necessary: i4 wins more efficiently than h3.

17. f4 h3 reconnected Blue to the k-edge, and f4 threatens Blue's connection to the a-edge, so Blue should keep Blue's win by defending Blue's connection to the a-edge with c9.

18. j2 Instead, Blue wastes a substantial fraction of a move, since Blue was already connected to the k-edge. (via j2 or a ladder from i3 that can climb to e8) Now, not only am I no longer able to prove that Blue wins, but I in fact prefer Red.

19. b4

5 was better ([[Minimax|minimaxing]]): It gives Red a [[ladder escape fork]] at b2, so the only advantage b4 might have over b5 is avoiding a potential [[peep]] at e2. However, that is almost-always much less important than the extra strength b5 gives along the a-edge. Furthermore, in this case, since Blue has e4 and e3,f2,g1,h1 are all empty, that peep provably achieves nothing: Red can just answer with e2 with d2, and f2+g1 will still be [[Captured cell|red-captured]].

However, even b5 is almost-certainly not enough here: If Blue responds in the cell Blue plays for 22, then the situation becomes the same as just after Blue plays 22 in the game. I would've played b9 instead of either of b4,b5 , due to Blue's strength towards the k-edge.

20. b3 If Blue was playing this as a timesuji [https://senseis.xmp.net/?TimeSuji], then I think Blue should've played g2 instead, so Blue would have more of them left. Otherwise, this was bad because redD2 [[Captured cell|captures]] e1+d1, and thereby [[Dead cell|kills]] b3. Red _might_ play b7 to try punishing b3, but I would probably instead neutralize b3 with a move near the a-edge.

----

21. g2 simple and fine, since this makes 20. b3 completely useless to Blue

22. d8 Very Good: Before I saw Blue play this, the position looked good for Red. With this move, I am almost-certain that Blue wins. (Blue does _not_ keep this almost-certain win.)

23. c8 Red's only chance c8 has a connection to the 1-edge, and c5 is an escape for ladders under c8, so the 1-edge direction is settled.

24. b9 blunder; now Red wins _Red_ keeps this win for the short rest of the game.

Blue needed to defend along the 11-edge, either immediately with b10 (simpler), or after threatening to cut through near the middle of the a-edge (b7 is faster).

<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 d3 e5 j3 f4 b4 1:g2 3:c8 5:c9 7:b7 B f6 e4 f5 h4 c3 c5 e8 h3 j2 b3 2:d8 4:b9 6:d7"/>

25. c9 forced

26. d7 Blue has a height-4 ladder. If Red just pushes, then Blue will connect to c5 which will then ladder to b9.

27. b7 Instead, Red [[Ladder_handling#Defending|yields]], winning.

28. Blue resigns b7 connects to the 1-edge via c6 or a6.

----

<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 d3 e5 j3 f4 b4 g2 c8 c9 *:b7 B f6 e4 f5 h4 c3 O:c5 e8 h3 j2 b3 d8 b9 d7 S area(e5,d5,b7,b8) f4 h1 area(g1,d1,d3,g3) c4 area(b4,a5,a7,b7) c7 b8 c8 area(c9,c11,a11)"/>

Against "O", "*" is the same defense as if a height-4 ladder is pushed too close to an a3 swap piece: In that case, the attacker might be anticipating a [[Foldback|foldback underneath]], but if the defender yields just before the attacker's push makes a bridge to the swap piece, then instead the the original _defender_ gets a height-2 ladder.

<hexboard size="5x4"
visible="-(b5 c5 d5 d4)"
edges="top left"
contents="R c4 1:c3 3:c2 5:a2 7:a3 9:a4 11:a5 B c1 d3 2:d2 4:d1 6:b2 8:b3 10:b4 12:b5"
/>

If Red pushes with c3, then Blue gets a [[Foldback|foldback underneath]]. Red should instead [[Ladder_handling#Defending|yield]] with b3, so that instead _Red_ gets a ladder.

<hexboard size="5x4"
visible="-(b5 c5 d5 d4)"
edges="top left"
contents="R c4 1:b3 3:c2 5:c3 7:d2 B c1 d3 2:(b1 a2 b2) 4:b4 6:d1"
/>

To avoid this, Blue should [[Ladder_handling#Attacking|pivot]] sooner.

← Older revision		Revision as of 23:16, 28 August 2022
Line 130:		Line 130:


−	23. c8 Red's only chance c8 has a connection to the top, and c5 is an escape for ladders under c8, so the upward direction is settled.	+	23. c8 Red's only chance c8 has a connection to the top, and c5 is an escape for ladders under c8, so the upward direction is [[settled region\|settled]].

← Older revision		Revision as of 02:13, 26 July 2022
Line 29:		Line 29:


−	You can see the diagram for each move by following along at [https://hexworld.org/board/#11c1,,a11f6e6e4g7f5h5h4c4c3d3c5e5e8j3h3f4j2b4b3g2d8c8b9c9d7b7:rw this ~~hexworld~~ link] .	+	You can see the diagram for each move by following along at [https://hexworld.org/board/#11c1,,a11f6e6e4g7f5h5h4c4c3d3c5e5e8j3h3f4j2b4b3g2d8c8b9c9d7b7:rw this HexWorld link] .

@@ Line 1: / Line 1: @@
-== Game Information ==
+== Game information ==
 * Size: 11x11
 * Red: FIFI25
@@ Line 7: / Line 7: @@
 * Location: [[Board Game Arena]], table [https://boardgamearena.com/table?table=212776246 212776246]
-== Coordinate Conversion and Directions ==
+== Coordinate conversion and directions ==
 This game was played with BGA's old hex implementation, so its coordinates and board orientation are different from what's shown on this page.  I apply a small rotation to show move coordinates and positions on this page:
@@ Line 21: / Line 21: @@
-== Moves and Comments ==
+== Moves and comments ==
@@ Line 96: / Line 96: @@
-. h3     his is locally good - Blue is being [[Tidiness|tidy]] before laddering along the right - and keeps Blue's win, but was not necessary:  i4 wins more efficiently than h3.   See [[#Blue's Connection Right|the variations for that]].
+. h3   This is locally good — Blue is being [[Tidiness|tidy]] before laddering along the right — and keeps Blue's win, but was not necessary:  i4 wins more efficiently than h3.   See [[#Blue's Connection Right|the variations for that]].
@@ Line 163: / Line 163: @@
-== Variations  and More Explanation==
+== Variations and more explanation==
@@ Line 171: / Line 171: @@
-=== Blue's Connection Right===
+=== Blue's connection right===
@@ Line 251: / Line 251: @@
-===the Situation on Top===
+===The situation on top===
@@ Line 280: / Line 280: @@
-===the Ladder Along the Bottom===
+===The ladder along the bottom===
@@ Line 296: / Line 296: @@
-===the Final Move===
+===The final move===

@@ Line 1: / Line 1: @@
-== Game information ==
+== Game Information ==
 * Size: 11x11
 * Red: FIFI25
@@ Line 14: / Line 14: @@
-References to the "left" and "top" etc. are to ''this'' page's orientation, ''not'' BGA's orientation.  (In particular, the left edge goes from a1 to a11 inclusive, and the top edge goes from a1 to k1 inclusive.)
+References to the "left" and "top" etc. work for ''this'' page's orientation and the default hexworld.org/board orientation, but ''not'' for the orientation shown at the boardgamearena.com link by Location under Game Information.  (In particular, the left edge goes from a1 to a11 inclusive, and the top edge goes from a1 to k1 inclusive.)
@@ Line 28: / Line 28: @@
 FIFI25 plays  1. a11

@@ Line 7: / Line 7: @@
 * Location: [[Board Game Arena]], table [https://boardgamearena.com/table?table=212776246 212776246]
-== Coordinate Conversion ==
+== Coordinate Conversion and Directions ==
 This game was played with BGA's old hex implementation, so its coordinates and board orientation are different from what's shown on this page.  I apply a small rotation to show move coordinates and positions on this page:
 (11;11) -> a11     (1;11) -> a1     (1;1) -> k1     (11;1) -> k11
@@ Line 28: / Line 31: @@
 FIFI25 plays  1. a11
-murasawa does _not_ swap, and plays  2. f6
+murasawa does ''not'' swap, and plays  2. f6
@@ Line 48: / Line 51: @@
-. g7     h7 would normally be better ([[joseki]]), but g7 is good here, since if Blue connects to the k-edge with   6. h5  ,   then  [[Peep|7. g5]]  works well with f6, due to [[Edge_templates_everybody_should_know#Fifth_row_edge_templates_with_two_stones|the edge template that f5+g5 would form]].
+. g7     h7 would normally be better ([[joseki]]), but g7 is good here, since if Blue connects to the right with   6. h5  ,   then  [[Peep|7. g5]]  works well with f6, due to [[Edge_templates_everybody_should_know#Fifth_row_edge_templates_with_two_stones|the edge template that f5+g5 would form]].
@@ Line 60: / Line 63: @@
-. c4     good ([[joseki]])   Blue is fairly strong towards the a-edge, so Blue will probably connect a-edge.  That means Red will probably need to ladder along the 1-edge, and c4 will be quite helpful with such a ladder.
+. c4     good ([[joseki]])   Blue is fairly strong towards the left, so Blue will probably connect to the left edge.  That means Red will probably need to ladder along the top, and c4 will be quite helpful with such a ladder.
@@ Line 78: / Line 81: @@
-. e5   This seemed fine  to me until I saw Blue's response :-).  Due to that response, Red should've tried j3 instead.  (j3 would create a ladder along the 1-edge towards a1 and a ladder along the k-edge towards k11.)
+. e5   This seemed fine  to me until I saw Blue's response :-).  Due to that response, Red should've tried j3 instead.  (j3 would create a ladder along the top towards the left and a ladder along the right towards the bottom.)
-. e8     This wins for Blue, though Blue did _not_ keep the win:   Due to c3, Blue can keep c5 connected _and_ serving as an escape for height-3 ladders (Red can't [[Foiling|foil]]), so Blue connects to the a-edge via f5 or c9.  For the k-edge, h4 gives Blue either a height-2 ladder plus a [[Switchback#Switchback_threat|switchback threat]] or a height-3 ladder, and either of those is enough to [[Climbing|climb]] to e8.
+. e8     This wins for Blue, though Blue did ''not'' keep the win:   Due to c3, Blue can keep c5 connected ''and'' serving as an escape for height-3 ladders (Red can't [[Foiling|foil]]), so Blue connects left via f4 or c9.  For the right, h4 gives Blue either a height-2 ladder plus a [[Switchback#Switchback_threat|switchback threat]] or a height-3 ladder, and either of those is enough to [[Climbing|climb]] to e8.
@@ Line 87: / Line 90: @@
-<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 1:d3 3:e5 5:j3 7:f4 9:b4 B f6 e4 f5 h4 c3 2:c5 4:e8 6:h3 8:j2 10:b3"/>
+<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 11:d3 13:e5 15:j3 17:f4 19:b4 B f6 e4 f5 h4 c3 12:c5 14:e8 16:h3 18:j2 20:b3"/>
-. h3   This is locally good - Blue is being [[Tidiness|tidy]] before laddering along the k-edge - and keeps Blue's win, but was not necessary:  i4 wins more efficiently than h3.
+. h3   This is locally good - Blue is being [[Tidiness|tidy]] before laddering along the right - and keeps Blue's win, but was not necessary:  i4 wins more efficiently than h3.
-. f4   h3 reconnected Blue to the k-edge, and f4 threatens Blue's connection to the a-edge, so Blue should keep Blue's win by defending Blue's connection to the a-edge with c9.
+. f4   h3 reconnected Blue to the right, and f4 threatens Blue's connection left, so Blue should keep Blue's win by defending Blue's connection left, with c9.
-. j2   Instead, Blue wastes a substantial fraction of a move, since Blue was already connected to the k-edge.  (via j2 or a ladder from i3 that can climb to e8)  Now, not only am I no longer able to prove that Blue wins, but I in fact prefer Red.
+. j2   Instead, Blue wastes a substantial fraction of a move, since Blue was already connected right.  (via j2 or a ladder from i3 that can climb to e8)  Now, not only am I no longer able to prove that Blue wins, but I in fact prefer Red.
 .  b4
-b5 was better ([[Minimax|minimaxing]]):     It gives Red a [[ladder escape fork]] at b2, so the only advantage b4 might have over b5 is avoiding a potential [[peep]] at e2.   However, that is almost-always much less important than the extra strength b5 gives along the a-edge.   Furthermore, in this case, since Blue has e4 and e3,f2,g1,h1 are all empty, that peep provably achieves nothing:  Red can just answer with e2 with d2, and f2+g1 will still be [[Captured cell|red-captured]].
+b5 was better ([[Minimax|minimaxing]]):     It gives Red a [[ladder escape fork]] at b2, so the only advantage b4 might have over b5 is avoiding a potential [[peep]] at e2.   However, that is almost-always much less important than the extra strength b5 gives along the left.   Furthermore, in this case, since Blue has e4 and e3,f2,g1,h1 are all empty, that peep provably achieves nothing:  Red can just answer with e2 with d2, and f2+g1 will still be [[Captured cell|red-captured]].
-However, even b5 is almost-certainly not enough here:  If Blue responds in the cell Blue plays for 22, then the situation becomes the same as just after Blue plays 22 in the game.   I would've played b9 instead of either of  b4,b5 ,  due to Blue's strength towards the k-edge.
+However, even b5 is almost-certainly not enough here:  If Blue responds in the cell Blue plays for 22, then the situation becomes the same as just after Blue plays 22 in the game.   I would've played b9 instead of either of  b4,b5 ,  due to Blue's strength towards the right.
-. b3   If Blue was playing this as a timesuji [https://senseis.xmp.net/?TimeSuji], then I think Blue should've played g2 instead, so Blue would have more of them left.  Otherwise, this was bad because redD2 [[Captured cell|captures]] e1+d1, and thereby [[Dead cell|kills]] b3.  Red _might_ play b7 to try punishing b3, but I would probably instead neutralize b3 with a move near the a-edge.
+. b3   If Blue was playing this as a timesuji [https://senseis.xmp.net/?TimeSuji], then I think Blue should've played g2 instead, so Blue would have more of them left.  Otherwise, this was bad because redD2 [[Captured cell|captures]] e1+d1, and thereby [[Dead cell|kills]] b3.  Red ''might'' play b7 to try punishing b3, but I would probably instead neutralize b3 with a move near the top.
@@ Line 121: / Line 124: @@
-. d8     Very Good:   Before I saw Blue play this, the position looked good for Red.  With this move, I am almost-certain that Blue wins.  (Blue does _not_ keep this almost-certain win.)
+. d8     Very Good:   Before I saw Blue play this, the position looked good for Red.  With this move, I am almost-certain that Blue wins.  (Blue does ''not'' keep this almost-certain win.)
-. c8     Red's only chance   c8 has a connection to the 1-edge, and c5 is an escape for ladders under c8, so the 1-edge direction is settled.
+. c8     Red's only chance   c8 has a connection to the top, and c5 is an escape for ladders under c8, so the upward direction is settled.
-. b9     blunder; now Red wins   _Red_ keeps this win for the short rest of the game.
+. b9     blunder; now Red wins   ''Red'' keeps this win for the short rest of the game.
-Blue needed to defend along the 11-edge, either immediately with b10 (simpler), or after threatening to cut through near the middle of the a-edge (b7 is faster).
+Blue needed to defend along the bottom, either immediately with b10 (simpler), or after threatening to cut through near the middle of the left edge (b7 is faster).
-<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 d3 e5 j3 f4 b4 1:g2 3:c8 5:c9 7:b7 B f6 e4 f5 h4 c3 c5 e8 h3 j2 b3 2:d8 4:b9 6:d7"/>
+<hexboard size="11x11" contents="R a11 e6 g7 h5 c4 d3 e5 j3 f4 b4 21:g2 23:c8 25:c9 27:b7 B f6 e4 f5 h4 c3 c5 e8 h3 j2 b3 22:d8 24:b9 26:d7"/>
@@ Line 144: / Line 147: @@
-.  Blue resigns     b7 connects to the 1-edge via c6 or a6.
+.  Blue resigns     b7 connects to the top via c6 or a6.
@@ Line 159: / Line 162: @@
-Against "O", "*" is the same defense as if a height-4 ladder is pushed too close to an a3 swap piece:  In that case, the attacker might be anticipating a [[Foldback|foldback underneath]], but if the defender yields just before the attacker's push makes a bridge to the swap piece, then instead the the original _defender_ gets a height-2 ladder.
+Against "O", "*" is the same defense as if a height-4 ladder is pushed too close to an a3 swap piece:  In that case, the attacker might be anticipating a [[Foldback|foldback underneath]], but if the defender yields just before the attacker's push makes a bridge to the swap piece, then instead the the original ''defender'' gets a height-2 ladder.
@@ Line 168: / Line 171: @@
   />
-If Red pushes with c3, then Blue gets a [[Foldback|foldback underneath]].  Red should instead [[Ladder_handling#Defending|yield]] with b3, so that instead _Red_ gets a ladder.
+If Red pushes with c3, then Blue gets a [[Foldback|foldback underneath]].  Red should instead [[Ladder_handling#Defending|yield]] with b3, so that instead ''Red'' gets a ladder.
 <hexboard size="5x4"

@@ Line 5: / Line 5: @@
 * Result: 1-0 (Red won)
 * Comments: Eric Demer
-* Location: [[Board Game Arena]], game [https://boardgamearena.com/table?table=212776246]
+* Location: [[Board Game Arena]], table [https://boardgamearena.com/table?table=212776246 212776246]
 == Coordinate Conversion ==
@@ Line 177: / Line 177: @@
 To avoid this, Blue should [[Ladder_handling#Attacking|pivot]] sooner.

← Older revision	Revision as of 09:38, 13 November 2021
(No difference)