David Boll Hex FAQ - Revision history

Selinger: Edited categories

2020-12-28T19:08:12Z

Edited categories

Selinger: small typo

2020-10-30T03:15:48Z

small typo

Selinger: Some more copy-editing.

2020-10-29T14:14:00Z

Some more copy-editing.

Selinger: Added a disclaimer.

2020-10-29T14:11:47Z

Added a disclaimer.

Selinger: More Wiki formatting of lists.

2020-10-29T13:56:42Z

More Wiki formatting of lists.

Selinger: Converted remaining ASCII boards to

2020-10-29T13:45:46Z

Converted remaining ASCII boards to <hexboard>

Selinger: Use "Red" and "Blue" instead of "V" and "H", to harmonize with most of this Wiki.

2020-10-29T13:39:14Z

Use "Red" and "Blue" instead of "V" and "H", to harmonize with most of this Wiki.

Show changes

Selinger: Fixed a mistake in the 4th row template (d4 is not part of the carrier).

2020-10-29T13:27:45Z

Fixed a mistake in the 4th row template (d4 is not part of the carrier).

Nickname: /* Edge techniques */

2017-03-21T14:19:15Z

‎Edge techniques

Nickname: /* Elementary concepts: the 2-bridge */

2017-03-21T14:14:33Z

‎Elementary concepts: the 2-bridge

← Older revision		Revision as of 19:08, 28 December 2020
Line 303:		Line 303:
	19. E8 Threatens to connect at D9 or F8; Blue has run out of tricks.		19. E8 Threatens to connect at D9 or F8; Blue has run out of tricks.
	Blue resigns.		Blue resigns.
		+
		+	[[category:Basic Strategy]]

@@ Line 104: / Line 104: @@
     />
-If the dashed hexes (or their mirror image) are clear, Red has a connect-
+If the dashed hexes (or their mirror image) are clear, Red has a connection.
-ion.  The basic idea is that either B3 or D3 will connect, and Blue can't
+The basic idea is that either B3 or D3 will connect, and Blue can't
 stop both.  Red need not defend this connection unless Blue moves into one
 of the dashed hexes.

@@ Line 34: / Line 34: @@
 while the second player attempts to form an unbroken chain of her hexes
 connecting the left side and the right.  To make subsequent diagrams
-clearer, the 2 players will be referred to as Blue and Red,
+clearer, the 2 players will be referred to as Red and Blue,
 with Red having the first move.  For notational purposes, the board
 is indexed by letter and number, like so:
@@ Line 42: / Line 42: @@
 == Elementary concepts: the 2-bridge ==
-Connectivity is the key to hex, consider the following game with Red to
+Connectivity is the key to Hex, consider the following game with Red to
 move next:
@@ Line 53: / Line 53: @@
 that matter in this game:  A4, A3, C3, and C2 and Blue has a response to all
 four of these moves.  If Red moves A4, Blue moves A3 (and vice versa), and if Red
-moves C3, Blue moves C2 (and vice versa).  So, hex players consider
+moves C3, Blue moves C2 (and vice versa).  So, Hex players consider
 hexes such as B3 and D2 to be connected, even though they do not touch,
 because a connection can be trivially forced.  By playing moves of this
@@ Line 73: / Line 73: @@
 the south edge (clearly), and one move away from being connected to the
 north edge in two different ways.  Blue can't stop both of these connections
-with only a single move.  So, if Blue and Red were good players, Blue would
+with only a single move.  So, if Red and Blue were good players, Blue would
-resign.  Of course, if Blue and Red were good players, the game wouldn't
+resign.  Of course, if Red and Blue were good players, the game wouldn't
 look like this, but that's beside the point!
@@ Line 162: / Line 162: @@
 are termed forcing moves, and understanding them is important.
-Another important concept in hex is the ladder.  Ladders occurs when
+Another important concept in Hex is the ladder.  Ladders occurs when
 both players place their pieces along one row or column.  They're
 usually forced by one of the two players, and they usually occur near
@@ Line 191: / Line 191: @@
-I'll close this section with some strategic generalities about hex:
+I'll close this section with some strategic generalities about Hex:
 # Always look for useful forcing moves.
@@ Line 240: / Line 240: @@
 == Sample Game (11x11 board) ==
-The following is an annotated transcript of a hex game.  Follow along
+The following is an annotated transcript of a Hex game.  Follow along
 with this on a board, and you could learn all kinds of stuff.  The
-players are Blue and Red, Red moves first.  Blue is a bit weak in the opening,
+players are Red and Blue, Red moves first.  Blue is a bit weak in the opening,
 but the mid game is wide open after a questionable move by Red.  Red ends
 up preserving the win by carefully maintaining the winning line

← Older revision		Revision as of 14:11, 29 October 2020
Line 1:		Line 1:
		+	''This page is a lightly edited version of David Boll's Hex FAQ [https://web.archive.org/web/20150906212829/http://www.mazeworks.com/hex7/hex_faq.html], written in 1994. Please note that some of the advice contained in this page is outdated; for example, modern players use the [[swap rule]], so opening in the center is not a viable opening.''
		+
	HEX: Answers to common questions.		HEX: Answers to common questions.

@@ Line 191: / Line 191: @@
 I'll close this section with some strategic generalities about hex:
-) Always look for useful forcing moves.
+# Always look for useful forcing moves.
-) When trying to connect to an edge, it is usually better to get an
+# When trying to connect to an edge, it is usually better to get an unassailable link to the edge first, then try to connect to the link.
-        unassailable link to the edge first, then try to connect to the link.
+# Play defense first, offense second - even when ahead.
-) Play defense first, offense second - even when ahead.
+# Remember the potential of ladders, and learn to see them as a single move.
-) Remember the potential of ladders, and learn to see them as a single
+# If you move first, you will win with perfect play.  Another way to look at this is:  Unless you make a mistake, you have a winning line (as the first player).  Find it.  Often the knowledge that you 'should' have a win helps you find it.
-        move.
+# Know the fundamentals of opening and edge connection.
-) If you move first, you will win with perfect play.  Another way to
-        look at this is:  Unless you make a mistake, you have a winning line
-        (as the first player).  Find it.  Often the knowledge that you 'should'
-        have a win helps you find it.
-) Know the fundamentals of opening and edge connection.
 == The opening ==
@@ Line 214: / Line 209: @@
     />
-  a:  Likely to get a response of H4 by Red.  If Blue then tries G5, Red replies
+* a.  Likely to get a response of H4 by Red.  If Blue then tries G5, Red replies H5 - and Blue is being locked out of the right edge.
-      H5 - and Blue is being locked out of the right edge.
+*  b:  Weak.  Red plays F5 or E5, and is one row closer to home.
-  b:  Weak.  Red plays F5 or E5, and is one row closer to home.
+*  c:  Now Red responds with E5
-  c:  Now Red responds with E5
+*  d:  Could be good, provided Red can't connect with G4.  I've never tried to work this out.  I3 also looks to be a decent response for Red, and both plays are strong defensive moves as well.
-  d:  Could be good, provided Red can't connect with G4.  I've never tried to
+*  e:  Like c, only weaker
-      work this out.  I3 also looks to be a decent response for Red, and both
+*  f:  The 'classic' defensive move.  Recall that moving in this position is the key to the best defense from 4 rows out, it's also typically the best position from which to defend on a wide open board.
-      plays are strong defensive moves as well.
+*  g:  Weak, leaves the left side of the board too wide open.
-  e:  Like c, only weaker
+*  h:  Seems to be a good defensive play, but I've never used it or seen it. Less offensive potential than f.
-  f:  The 'classic' defensive move.  Recall that moving in this position is
-      the key to the best defense from 4 rows out, it's also typically the
-      best position from which to defend on a wide open board.
-  g:  Weak, leaves the left side of the board too wide open.
-  h:  Seems to be a good defensive play, but I've never used it or seen it.
-      Less offensive potential than f.
 So, if both players move typically, the opening will be 1. F6 G3, or some
@@ Line 243: / Line 232: @@
 ways in which this can happen:
-)  The first player cannot open on the main diagonal.  I've only played this
+# The first player cannot open on the main diagonal.  I've only played this version twice as the opener, one time I opened as close to the center hex as possible, and another time I opened at F4 (on a 11x11).  The first player still has the advantage.
-      version twice as the opener, one time I opened as close to the center
+# The often-discussed 3 move equilization:  One player constructs a position with two moves by Red and one move by Blue, and the second player chooses who plays which side.  If the opening position is carefully constructed, the game is quite playable.
-      hex as possible, and another time I opened at F4 (on a 11x11).  The
+# Even simpler:  one move equilization.  It has been proved that opening in the acute corner is a losing move for Red, so perhaps placing a Red near an acute corner, then letting the other player choose sides would be workable in Hex.  I've tried this once, and it seemed OK.
-      first player still has the advantage.
-)  The often-discussed 3 move equilization:  One player constructs a
-      position with two moves by Red and one move by Blue, and the second player
-      chooses who plays which side.  If the opening position is carefully
-      constructed, the game is quite playable.
-)  Even simpler:  one move equilization.  It has been proved that opening in
-      the acute corner is a losing move for Red, so perhaps placing a Red near
-      an acute corner, then letting the other player choose sides would be
-      workable in Hex.  I've tried this once, and it seemed OK.
 == Sample Game (11x11 board) ==

@@ Line 142: / Line 142: @@
 to you later.  Here's a rather contrived example:  (Red to move and win)
-                    A B C D E F G H I
+<hexboard size="9x9"
-   . . . . . . . . .
+   coords="show"
-   . . . . . . . . .
+   contents="R e4 d5 f5 B b8 d7 f7"
-   . . . . . . . . .
+   />
-   . . . . V . . . .
-   . . . V . V . . .
-   . . . . . . . . .
-   . . . H . H . . .
-   . H . . . . . . .
-   . . . . . . . . .
 From our study of edge connection techniques, we know that the hexes
@@ Line 171: / Line 165: @@
 an edge.  Here's an example, Blue to play:
-                    A B C D E F G H I
+<hexboard size="9x9"
-   . . . . . . . . .
+   coords="show"
-   . . . . . . . . .
+   contents="R d3 c6 g6 i6 i8 B b8 d7 e8 g7"
-   . . . V . . . . .
+   />
-   . . . . . . . . .
-   . . . . . . . . .
-   . . V . . . V . V
-   . . . H . . H . .
-   . H . . H . . . V
-   . . . . . . . . .
 Note that Blue is connected from the left almost all the way across, but
@@ Line 190: / Line 179: @@
 has an additional piece at H2, so the board looks like this:
-                    A B C D E F G H I
+<hexboard size="9x9"
-   . . . . . . . . .
+   coords="show"
-   . . . . . . . H .
+   contents="R d3 c6 g6 i6 i8 B b8 d7 e8 g7 h2"
-   . . . V . . . . .
+   />
-   . . . . . . . . .
-   . . . . . . . . .
-   . . V . . . V . V
-   . . . H . . H . .
-   . H . . H . . . V
-   . . . . . . . . .
 Now Blue can play the same ladder sequence as before - but this time,
@@ Line 225: / Line 209: @@
 small letters in the diagram below:
-                  A B C D E F G H I J K
+<hexboard size="11x11"
-   . . . . . . . . . . .
+   coords="show"
-   . . . . . . h . . . .
+   contents="R f6 E a:f5 b:g5 c:g4 d:f4 e:h4 f:g3 g:h3 h:g2"
-   . . . . . . f g . . .
+   />
-   . . . . . d c e . . .
-   . . . . . a b . . . .
-   . . . . . V . . . . .
-   . . . . . . . . . . .
-   . . . . . . . . . . .
-   . . . . . . . . . . .
-  . . . . . . . . . . .
-  . . . . . . . . . . .
    a:  Likely to get a response of H4 by Red.  If Blue then tries G5, Red replies

@@ Line 111: / Line 111: @@
 <hexboard size="7x7"
-    contents="E +:d4 R e4 E +:f4 E +:c5 E +:d5 E +:e5 E +:f5 E +:g5 E +:b6 E +:c6 E +:d6 E +:e6 E +:f6 E +:g6 E +:a7 E +:b7 E +:c7 E +:d7 E +:e7 E +:f7 E +:g7"
+    contents="R e4 E +:f4 E +:c5 E +:d5 E +:e5 E +:f5 E +:g5 E +:b6 E +:c6 E +:d6 E +:e6 E +:f6 E +:g6 E +:a7 E +:b7 E +:c7 E +:d7 E +:e7 E +:f7 E +:g7"
     />

@@ Line 87: / Line 87: @@
 the bottom edge, the template looks like this:
-          . V
+<hexboard size="2x2"
-           - -    <- edge
+    contents="R b1 E +:a2 E +:b2"
 If the 2 hexes below V are clear, V is connected.  If H moves to one of the
@@ Line 96: / Line 97: @@
 rows away:  The template is the following:
-       A B C D
+<hexboard size="4x4"
-  . . . .
+   coords="hide"
-  . . V -
+   contents="R c2 E +:d2 E +:b3 E +:c3 E +:d3 E +:a4 E +:b4 E +:c4 E +:d4"
-  . - - -
+   />
-  - - - -
 If the dashed hexes (or their mirror image) are clear, V has a connect-
@@ Line 109: / Line 109: @@
 rows away:  This is more complicated:
-     A B C D E F G
+<hexboard size="7x7"
-  . . . . . . .
-  . . . . . . .
+    contents="E +:d4 R e4 E +:f4 E +:c5 E +:d5 E +:e5 E +:f5 E +:g5 E +:b6 E +:c6 E +:d6 E +:e6 E +:f6 E +:g6 E +:a7 E +:b7 E +:c7 E +:d7 E +:e7 E +:f7 E +:g7"
-  . . . . . . .
+   />
-  . . . - V - .
-  . . - - - - -
-  . - - - - - -
-  - - - - - - -
 If H moves into this region, but doesn't move to one of {D5,E5,D6,C7,D7},

@@ Line 43: / Line 43: @@
 move next:
-         A B C D
+<hexboard size="4x4"
-  V . . .
+   coords="hide"
-  . . . H
+   contents="R a1 B d2 B b3 R d4"
-  . H . .
+   />
-  . . . V
 No matter where V moves, H has the game won! There are only four hexes
@@ Line 62: / Line 61: @@
 subtly, as in the following example:  (H to move)
-           A B C D E F G H I
+<hexboard size="9x9"
-  . . . . . . . . .
+   contents="R h2 R c3 R h3 R d4 R g5 R c6 B d6 B e6 B f6 R g6 B g7 B b8 R d8 B f8 B b9"
-  . . . . . . . V .
+   />
-  . . V . . . . V .
-  . . . V . . . . .
-  . . . . . . V . .
-  . . V H H H V . .
-  . . . . . . H . .
-  . H . V . H . . .
-  . H . . . . . . .
 Although the game might appear close at first glance, V has a clear win.