In an old problem of the week, Robertie describes classifying errors by position type.

Mr. Robertie: Are you willing to share / list these position types?

Here's a sample taxonomy for cash game positions:

The Early Game
Blitzes and Action Doubles
The Middle Game
Holding Games
Prime and Blocking Games
Ace-Point and Deuce-Point Games
Back Games
Post-Ace-Point Games
Miscellaneous Endgames
Races and Bearoffs

Each type includes both checker play and cube positions, and every position will fit somewhere in this list. Two categories function as catch-alls: 'The Middle Game' includes all positions which are too far along to be considered as early positions, but which haven't yet resolved into one of the other types; 'Miscellaneous Endgames' does the same for endings where you're bearing in or bearing off against contact.

While I appreciate the response you must be holding back.

Example: in POTW #66 you mention position types being as detailed as 2-4 backgame , to be crossed with tactics with examples being slot or not.

I bet your classification system is much much more detailed than what you shared here. Probably hundreds of position types.

I'd imagine you must have detailed categories within backgames:
probably each type (1-2,1-3,2-4, etc) crossed with hit or not, slot or not, enough timing, etc.

Same for each generic position type you mentioned above. Are you willing to share these?

Clearly each position type can be then broken down into dozens of sub-positions. As you say, each back game configuration could be considered as its own type. Back games where the back game player's home board has collapsed play very similarly, hence could be yet another type, etc.

Will I share my detailed list? Nope, too long. You'll learn more by gradually building your own.

"You'll learn more by gradually building your own."

Possibly true but certainly not your reason. And a plane brought down building 7 too! ha ha ha ha

A friend recently asked me what categories I use. Below is the list I assembled for him.

I use a Microsoft Access database to store the positions I think are worthy. Using database software, I can tag a position with as many different categories as I like. Most get two or three.

I use about 100 different categories. The complete list is given below. (I know its a bit of a mess. One or two categories are duplicated, for instance.)

A holding game position might be tagged as follows:

• Holding Game
• A5-Anchor on 5pt.
• Cube action

A bear-in might be described using these:

• Bearing In
• Bearing In -- Against Opposition
• Bearing In -- Going for the gammon
• 2 Checkers on Bar

In addition to categories, each position can have notes attached.

Here is the list:

"1 Checker on Bar"
"2 Checkers on Bar"
"3 Checkers on Bar"
"4+ Checkers on Bar"
"A1 — Anchor on 1pt"
"A2 — Anchor on 2pt"
"A3 — Anchor on 3pt"
"A4 — Anchor on 4pt"
"A5 — Anchor on 5pt"
"A6 — Anchor on 6pt"
"A7 — Anchor on 7pt"
"A8 — Anchor on 8pt"
"Ace Point — Cover blot on ace point"
"Ace Point — Hit loose on ace point"
"After a Late Hit — Checker Play"
"After a Late Hit — Cube Action?"
"After Bar Point Is Made — Roll 6-x"
"After Escape"
"Anchor — Inside or Out"
"Anchor or Split"
"B21 Backgame"
"B31 Backgame"
"B32 Backgame"
"B321 Backgame"
"B41 Backgame"
"B42 Backgame"
"B421 Backgame"
"B43 Backgame"
"B431 Backgame"
"B432 Backgame"
"B51 Backgame"
"B52 Backgame"
"B521 Backgame"
"B53 Backgame"
"B531 Backgame"
"B532 Backgame"
"B54 Backgame"
"B541 Backgame"
"B542 Backgame"
"B543 Backgame"
"Backgame"
"Backgame — Defense — Bearing In"
"Backgame — Offense"
"Backgame Defense"
"Bagai"
"Bananas Split"
"Bear In"
"Bear In — Against Opposition"
"Bear in — Going for the Gammon"
"Bear In — Unopposed"
"Bear Off"
"Bear Off — After a late hit"
"Bear Off — Against Opposition"
"Bear Off — Break Inside/Leave Gap"
"Bear Off — Fewer than Possible"
"Bear Off — Fill Gap or Smooth?"
"Bear Off — Four point"
"Bear Off — Going for the Backgammon"
"Bear Off — Going for the Gammon"
"Bear Off — One or None?"
"Bear Off — Opponent on bar"
"Bear Off — Unopposed"
"Bear Off Less than Possible"
"Blitz"
"Blitz — Cube Action"
"Blitz — Early"
"Blitz — Middle Game"
"Blot Hitting Contest"
"Break from Rear?"
"Break inside point to hit inside"
"Bust Board?"
"Coming under the Gun"
"Crashed Board"
"Cube Action"
"Diversification"
"DMP — Double Match Point"
"Do not split against a big stack"
"Double Hit Loose in Inner Board?"
"Doublets 11"
"Doublets 22"
"Doublets 33"
"Doublets 44"
"Doublets 55"
"Doublets 66"
"Doubling — Both back men escaped"
"Doubling — From the Bar"
"Doubling — Opponent on Bar"
"Dump play"
"Duplication"
"Early Game"
"Early Game — Cube Action"
"Early Game — Hit Loose on 3 Point"
"Early Pass"
"Five Point"
"Five Point — Make Either, Not Both"
"Free Drop"
"G1 — Guard on 1pt"
"G2 — Guard on 2pt"
"G3 — Guard on 3pt"
"G4 — Guard on 4pt"
"G5 — Guard on 5pt"
"G6 — Guard on 6pt"
"G7 — Guard on 7pt"
"GG — Gammon Go"
"GS — Gammon Save"
"Guard and Anchor"
"Hara Kiri"
"Hit loose on three point"
"Hit Twice or Hit and Cover"
"Hit?"
"Holding Game"
"Holding Game — Break anchor"
"Kauder Paradox"
"Keep Prime or Attack"
"Match Point"
"Middle Game"
"Middle Game — Cube Action?"
"Move Outside or Fill Gap Inside"
"Mutual Holding Game"
"Non-Contact Race"
"One Checker Back"
"One Checker Back — Slotting against"
"One Checker Primed"
"Opening Move"
"Pay Now or Pay Later"
"Pick and Pass"
"Picking up a second checker"
"Play Safe or Unstack"
"Point?"
"Post-Ace-Point Game"
"Pottle"
"Pre-clear"
"Prime versus Prime"
"Prime versus Prime — Cube action"
"Race Leader on Roll"
"Race Trailer on Roll"
"Reply to Opening Move"
"Reply to Opening Move — 62, 63, 64"
"Rolling a Prime Forward"
"Safe or bold?"
"Safety First"
"Saving the Gammon"
"Slot and Split"
"Slot Bar Point"
"Slot Happy"
"Slot Opponent's Bar Point"
"Slot or Not?"
"Splitting Inside"
"Stack or Spread"
"Stay back from big stacks"
"Switch Points"
"Switch Points — Bar for Five Point"
"Tempo Hit or Not?"
"To Hit or Not To Hit"
"To Slot or Not To Slot"
"Too Good To Double?"
"Trap Play"
"Trapped Behind Prime"
"Trouble Numbers"
"Two Checkers Primed"
"Voluntary Double Shot"
"Voluntary Single Shot"
"Who's Blocking Whom"

Hope this helps.

Mike

With all respect, i think that too many categories only make things more confused. If you are a strong intermediate player or a weak advanced, i think that 25-30 categories are more than fine, and cover almost all bg position

I actually think that Mike's list is pretty small. I can think of a bunch more categories not on it. And thanks for posting the list, it is a good jumping point for study.

I don't want to disagree with this, but I want to explain that my system gives you a choice to have the smaller list if you so choose. That's why I have general categories, such as "Holding Game" and "Backgame," and a set of subcategories, e.g., "B31 Backgame," "Backgame - Defense," "Backgame - Offense," and so on. Each position in my database is tagged first with a general category and then with one or more subcategories.

If I want, I can review all Backgames as a group. Or, if I am interested in the specifics of how to defend against the 31 Backgame, I can do that too. I'm not sure if you know, for instance, that the 31 backgame defender has trouble playing safely when he rolls 5 or 3. Those are the numbers that are blocked when he tries to break the 6pt. That means that building a surprisingly large stack on the 5pt during the bear-in can be beneficial in that specific type of game. This is an example of the type of information that can be revealed when you telescope down to a small subcategory.

Mike

I try to be more clear.

In theory you can add another thousand position at that list, and you will be more precise than Mike. And eventually you can add another thousand and you likely cover all possible bg position-type.

The problem is to remember them. And to actually use them in game.

I don't know: maybe my memory is not the best and simply anyone but me can remember hundred and hundred things without any problem. But when I play with most people on gridgammon and on backgammon NJ I simply noticed that many people have a very huge confusion in the thinking process:

People take very hopeless cubes, make three or four 0.3-0.4 blunders a game, they forget to make automatic double, they always open 6-4 making the 2 point even in gammon save positions. And they are not the worst players.

BG is obv a very hard game, and I belive that if you want to be very good you have to enlarge your bg reference positions. But for 90% of player I think that it's a useless work,because you have to start from few position, understand them very well and then add few more and then understand.

And understand= digest them and acutally use in game.

Interesting idea Mike.

Can you describe how your database works?

I'll take a few guesses.

You have a single table.
Each unique position stored / identified by XG position ID.
You have the hundred flags you mentioned in your earlier post, which are yes/no fields.
You tag as many fields as you want.

Then you can later query your database of positions for study later.


If above is right, do you not have any analysis stored to go with the position?

This is an ingenious idea on your part by the way.

Glad to.

The main table is the Position table, keyed by an autonumber field. It includes fields for GnuBgID, XGID, diagram, source, and notes (i.e., analysis).

A second table is the Category table, keyed by another autonumber field. It includes fields for CategoryName and CategoryDescription. I considered creating a table for Subcategories, but eventually decided to simply enter them as categories.

A third table is CategoryPosition. It is the "linker" table whose records contain keys for both the Position and Category tables. It establishes a "many-to-many" relationship between Position and Category. That means that each Position can be assigned to many Categories and, conversely, that each Category can be assigned to many different Positions.

Hope this helps. Sorry if the relational database jargon is a bit technical.

Mike

Mike has done a brilliant job here, thank you very much!!

while some of these categories may appear to overlap to a intermediate-I doubt they do to a stronger player, and by that line of thinking when you can differentiate them you have improved.


Taking it a step farther, i am sure more can be added, of course some themes are much more common than others, and therefore have more instances, that shouldn't stop anyone from expanding the library Mike has developed. I'd bet all I could beg, borrow and steal that Mike didn't start off with this library, its grown over time as he has improved.


It's a great gesture for Mike to share this with us and I'm very grateful that he was so kind.


best

eric

This is the difficult part for me, BG is easy

I am in despair after reading this thread. How do you even begin to categorise to this degree?

No need to despair. Most tournament players (even most very successful ones) don't do anything like this. They play and look at some positions, and play some more and look at a few more positions, and do some rollouts. Eventually they absorb a lot of knowledge and get to be pretty good.

If you want to get a specific piece of information at some point, you can usually set up a few similar positions, do some rollouts, and get a very reliable answer quickly. For instance, suppose you had a position come up in a game where you had escaped your back checkers and your opponent still had two checkers on your 5-point. You doubled and your opponent took, and eventually he threw a couple of doubles and won. Afterwards you wondered if you had doubled too soon. So you set up a few positions of this type, moving the checkers around so in one you had a 10-pip lead, in the next a 20-pip lead, and so on. Then you put them into XG and see which ones were doubles.

When you're done, you know how to handle the cube in this very common type of position. Keep doing things like that when interesting and typical positions come up, and over time you'll be a much better player with a modest amount of effort. It's really not all that hard. Persistence pays off over time.

What Taper_Mike has done with his categories is more of a reflection of a learning process and less a reflection on a recollection-for-decision-making process.

When looking at a position, there are many structures that can be considered as being meaningful. For example, it could be A3 (Anchor on 3 point) or it could be A4 (Anchor on 4 point). Is there a difference? Yes. Does that difference mater? Maybe, but often not. It depends on what else is going on, what the roll was, what the match score is, and all of that.

In the learning process, you've got to take in all of that information to learn to decide what is important and what isn't important as you learn to weigh this against that. Having a handful of similar positions to look at and think about is useful for this, and his labeling will give him access to that relatively easily.

But in the actual playing of the game, he's not going to sit there and think to himself: "I have 14 positions that are categorized as A3. One of those positions will tell me what to do in this spot." Instead, he's going to use the system of weighing this against that he developed over the course of reflecting on all of those positions on the current position. It will be more like "In this position -- where I have a middle anchor, the match score is whatever, the race is something, and with some other stuff floating in my head -- I think concept X is more useful than concept Y. Play A works with concept X better than play B, so I'll make play A."

I thought the gammon-save move with 6-4 was making the 2-pt.

Here http://www.bkgm.com/openings.html
Scroll down until you find 6-4 opening. Making the 2 point is a gammon go move and when you play 6-4 run you often escape one checker and its almost impossible to lose a gammon