User:Selinger

Proposed page: Question

A question is a move that forces a player to choose between two or more available options in an area of the board. The player can either answer the question, by playing one of the available responses, or not answer and play elsewhere. However, if the original question is sufficiently forcing, it must be answered right away.

Sometimes a player has a choice of accomplishing one of several different things in a given region, such as: choosing to connect one stone vs. another, connecting more strongly vs. denying the opponent a ladder escape, etc. In such situations, it is often in the player's interest to postpone the choice as long as possible, to keep their options open until they know more about what is going on on the rest of the board. By playing a question, the opponent can sometimes force them to make the choice earlier than they would have liked.

Of course, in some very general sense, every move is a question, namely the question: "How will you respond to this move?". But usually the term is applied more narrowly in some region of the board that is not quite settled, where one player plays a move that forces the other player to settle it in one of several ways.

Example: U-turn

Perhaps the simplest example of a question is playing in the center of a U-turn. The U-turn is the following position, consisting of two overlapping bridges:

With Blue to move, Red has a choice between connecting A to B or connecting A to C, but Red cannot achieve both of these things simultaneously. By playing in the cell marked "*", Blue asks the question "which or B or C do you want to connect to?"

The following is a position where asking this question is the only winning move for Blue:

With Blue to move, in the upper part, Blue gets to choose whether Red connects B or C to the top edge. In the lower part, Blue can force Red to choose whether to connect B or C to the bottom edge. By playing the question at "*", Blue forces Red to make this choice. If Red chooses B, Blue blocks B on top and vice versa.

Example: Edge template with two stones

Consider the following edge template:

This template has the curious property that, with Blue to move, Red can choose to connect either A or B to the edge, but cannot guarantee to connect them both. (See edge templates V-2g and V-2h).

Blue can ask the question "Which stone to you want to connect?" by playing at either of the cells marked "*". Red does not need to decide right away. For example, in the below diagram, if Blue intrudes at 1 and Red responds at 2, Red still retains the potential to connect either stone. But if Blue then plays at 3, then Blue threatens to cut off A at x or B at y. Red cannot defend both.

Similar, if the game proceeds like in the next diagram, then after move 7, Blue threatens to cut off A at x or B at y, and Red cannot save both connections.

Of course, there are many other lines of play to consider. If Blue is not careful at each move, Red might be able to connect both A and B. But if Blue plays correctly, Red is eventually forced to answer the question.

Example: Template intrusion

Consider the following position, with Blue to move:

Note that Red is connected to the edge by edge template V2b, as highlighted. Blue would like to intrude into this template to gain strength either on the left or on the right.

Blue would like a 4th row ladder escape on the left. But the problem is that if Blue moves at d9 or c10, Red can reconnect by playing at h7, which is bad for Blue.

Blue would also like a 4th row ladder escape on the right. But again, the problem is that if Blue moves at g10 or g9, Red can reconnect at g8, or by playing a minimaxing move, say at b10:

Neither of these outcomes is great for Blue. Instead, what Blue can do is ask the template a question:

Basically, the question is: "How do you want to reconnect?" And based on the answer, Blue will be able to gain some strength on the left or on the right, without giving Red quite as much territory as would otherwise have been the case.

For example, if Red reconnects at e8, then Blue can play e10:

Now Red's mustplay region consists of the 6 highlighted cells. If Red plays at d9, Blue gets a forcing move at b10, giving Blue a 4th row escape on the left, without Red getting g8. If Red plays at d10, g8, or g10, Blue gets a forcing move at d9, giving Blue a 4th row escape on the left without Red getting g8. If Red plays at g9, Blue defends the bridge at f9 and then plays as before. Finally, if Red plays at f10, Blue can respond at g8, getting a 4th row escape on the right. Although Red can still reconnect at b10, taking away Blue's ladder escape on the left, Red does not have the option of getting g8.

To be continued... and simplified?

To do

Add other illustrative examples, such as a template intrusion that forces the player to trade-off between a stronger connection and letting the opponent get a ladder escape, etc.

Also point out that Josekis are essentially sequences of questions and answers.