code: void drawEmptyBoard(Graphics g) {
          int x=x_offset, y=y_offset;
          Color old_col=g.getColor();
  
          g.setFont(def_font2);
          old_col=g.getColor();
          g.setColor(checksum_col);
          g.drawString(("Checksum: " + checksum), x_offset + field_size, y_offset - 20);
          g.setFont(def_font);
          g.setColor(old_col);
  
          for(int i=0; i < num_fields; i++) {
              for(int j=0; j < num_fields; j++) {  // draws 1 row
                  g.drawRect(x, y, field_size, field_size);
                  x+=field_size;
              }
              g.drawString((String.valueOf((num_fields - i - 1))), x + 20, y + field_size / 2);
              y+=field_size;
              x=x_offset;
          }
  
          for(int i=0; i < num_fields; i++) {
              g.drawString((String.valueOf(i)), x_offset + i * field_size + field_size / 2, y + 30);
          }
      }
docs: Draws the empty board, no pieces on it yet, just grid lines