anchor.diff:          _ -> ?null
       end.
   
  +crd_enc({C, R}) ->
  +    [$a + C - 1, $1 + R - 1].
  +
   crd_inc({C, R}, {CS, RS}) ->
       Crd = {C + CS, R + RS},
       case crd_ok(Crd) of
  
positive.code:     end.
  
  crd_row({_, R}) -> R.
  crd_col({C, _}) -> C.
  
  crd_ok({C, R})
    when C >= 1 andalso C =< 8 andalso
  
negative.code: 
  is_valid_move_(?GAME_CLASSIC, Table, TurnColor, Move) ->
      {C1, C2} = move_dec(Move),
      {MyColor, Figure} =
          case cell(Table, C1) of
              ?empty -> throw({error, {cell_is_empty, C1}});
              {TurnColor, _} = Figure0 -> Figure0;
  