My Android app Senior Chess

Senior Chess is an Android application based on my older chess program Queen. Besides playing chess games in the default Play mode, you can also use the Edit mode to set up positions and let Senior Chess search for the best move.

Senior Chess is available for free at Google Play Store Here is a video of a game, with Senior Chess deliberately playing Black and as weakly as possible (which is weaker that you would expect!).

Here are some tips about the commands available in the options menu:

New game
This introduces the start position, but you should be aware that it does not reset some other settings, such as thinking time and view of the board.

Undo last move
This command goes back a full move, that is, a half-move for each side. Since version 2.21 there is also an Undo button on the screen for this purpose. There is no special command to redo this full move.

Switch sides
If, for example, you play White, this command will make the computer play White and you Black. This is the case in Play mode. In Edit mode, discussed below, the name of this is Change side to move. A red dot in a corner of the board indicates the side that is to move.

Go (machine to move)
In Play mode, this is similar to the previous command: you can use it to make the computer, instead of yourself, make the next move. In Edit mode, you use this command to switch to Play mode and let the computer play the next move. This Go command is also useful to go back to normal Play mode after using Only user moves mode, as discussed next. When the machine is 'thinking' this command is temporarily replaced with the command Move now (stop thinking), as discussed below under Level

Only user moves
This command is useful when, in some postion, you want to make some moves for White and Black yourself. Use the Go command to go back to normal Play mode.

Edit mode
This enables you to set up any position. You can move pieces on the board as you like, adding pieces to the board and removing them. The latter can be done either by moving them to the row of pieces shown below the board or by clicking twice on a piece. When you go to the edit mode, you have to choose between starting either with the current position or with an empty board, the latter being useful to set up endgame positions. As discussed above, the Change side to move command can be used in this mode. To be able to end the edit mode, the command text Edit mode has temporarily been replaced with Leave edit mode. After leaving edit mode, you can either make a move yourself or use the command Go (machine to move)

Position...
This opens the sub menu with the following commands:

• Open position (FEN)
  to open a chess position that you saved earlier.

• Save position (FEN)
  to save a chess position so you can open it later.

• Delete FEN file
  to remove position files that you do not need any longer.

• Copy position to clipboard (FEN)
  to create a single text line representing the current position. Note that you can paste this not only in Senior Chess but in any app that allow pasting text.

• Paste position from clipboard (FEN)
  to set up a chess position coded in FEN format on the clipboard.

• Test position, selected at random
  see next command.

• Test position, selected by number
  Both this and the previous command use.
  (a)300 test positions taken from the well-known test suite WAC, published in the book Win at Chess by Fred Reinfeld (1958, 2001), Dover Books on Chess, and
  (b) 100 endgame positions. The latter are a subset from those found here.
  You are encouraged to find the best move, which is visible in algebraic notation during a few seconds when the position is loaded.

Game...
This introduces a submenu with the following commands:

• Open game (PGN)
  to open a chess game that you saved earlier. After opening a game from a PGN file, first an animation of the game is played. You can stop this animation by using the Stop movie command of the options menu (where it temporarily replaces the Undo last move command, discussed above). Then you can view all moves of the game and their resulting positions, traversing the game by going backward and forward through the game. You can do this by touching buttons displayed below the board. While doing this, there is a command Use current position to play so you can end the traversing mode. After this, you can either make a move yourself or use the command Go (machine to move).

• Save game (PGN)
  to save a chess game so you can open it later. (This command is enabled only for regular chess games, with standard initial position.)

• Delete PGN file
  to remove game files that you do not need any longer.

• Copy game to clipboard (PGN)
  to create a PGN file (in well-readable format) representing the current game. (This command is enabled only for regular chess games, with standard initial position.) You can then use the clipboard to paste the game not only in Senior Chess but in any app that allow pasting text. For example, you can paste it in an e-mail or a whatsapp message to send it to others.

• Paste game from clipboard (PGN)
  to view a chess game available as a PGN file as the current contents of the clipboard.

Level
The chosen level applies to the time the machine 'thinks' for each move. You can think yourself as long as you like. The level can be changed during a game, even while the machine is 'thinking'. This is important in connection with the Infinitely long thinking level. You can use this level to see how long it takes Senior Chess to find the best move in difficult chess problems. During thinking the best move found so far is displayed, along with a score. When you want the machine to end thinking and make this move, use the command Move now (stop thinking), which replaces the command Go (machine to move), discussed above, as long as the machine is thinking. In version 1.59 (August 2014) and higher, it is possible to let Senior Chess occasionally make weak moves, so that low- or moderate-level human players have a chance to win. Such moves are also known as odd or handicap moves. Odd moves are usually very weak ones. You can set the frequency of odd moves as you like. After selecting the level Possibly weak moves..., the user can specify the percentage of machine moves that should be such odd moves. After entering 100, all moves will be odd moves, which enables even absolute beginners to win. If you win too easily this way, use a lower percentage, such as 25, causing about one out of every four moves to be an odd one.

View
Use this to rotate the board. Using this command when you are viewing the position from the usual perspective of White, you will view it from the viewpoint of Black, and vice versa.

Sound On/Off
By using this command you can switch sound on and off. Default is sound off.

Help
This shows both a version number and a link to this web page.


About the word Senior in the name
The word Senior refers to myself, not to the users of this app. The other day, my son gave me an interesting (Dutch) book about the brains of seniors, just when I was desperately trying to find a suitable name for my chess app. Having programmed for more than 50 years, I don't exaggerate when claiming that the app was written by a senior. I might as well mention that as early as 1960 I passed a programming test, a certificate of which was handed out to me and signed by Dr. Max Euwe, who was the head of de Stichting Studiecentrum voor Administratieve Automatisering in Amsterdam, which had to do with programming. Euwe was a very well-known Dutch grandmaster and World Chess Champion from 1935 to 1937. So much about the word Senior in the name, which I hope will not frighten away any potential users younger than myself.

Leen Ammeraal