THE MOVE AND ITS VAGARIES.

Otago Witness, Issue 2672, 31 May 1905, Page 62

THE MOVE AND ITS VAGARIES.

(By James Mulvey.)

No. VT.

As I pointed out in former articles, it is the removal of the men from the different systems which causes the alteration in the "move." A treble exchange, or three for three, removes six men from the board, of which five may be in ono system, and one in the other, or four and two, or three and three respectively, or t!he whole of them may be removed from one system. If the removal of the men were the only thing we had to consider ,it would be comparatively easy to decide the effect on the "move," "out this is not all. During the progress of the exchange there may be a number of waiting moves, which must not be overlooked, or we will find our calculations of no avail.

After the exchange is completed .there is another important point which must not be left out, md that is, whose turn to play will it be — your own or your opponent's? There are thus three elements to be considered, but these may be reduced to one, in order to simplify matters. We will suppose it is our turn to play, then we will calculate up to the first move we make after the exchange ia completed. Our first consideration i& the six men actually removed from the board, of which the numbers in each system will either be both even of both odd. As both systems are the same as regards odd or even, it is necessary for us to count the men removed from one system only. Otir second consideration is the number of waiting moves. Each waiting move is played from one system into the other, aJid therefore alters the total in both systems from odd to even, or vice versa. We will, therefore treat each waiting move as a piece removed from one system by the exchange. It is only necessary to count the waiting moves made by pieces which are not removed from the board. Those moves made by pieces which are taken off during the progress of the exchange do not affect our calculations in any way. If it will be our own turn to play after the exchange is completed, well and good, but if our opponent's, then it will be necessary to add another to our total, as his move alters the total in the different systems. I have explained the details very fully, in order that even the beginner may grasx> them without the slightest difficulty. To reduce these to concrete form, we can make the following rule to govern this exchange — or in fact any species or exchange, no matter how many pieces aside are removed: — "Count the number of pieces removed from one system only, and then add to them the number of single or waiting moves, including your opponent's if it ia his turn to play after the exchange is completed, but do not include any waiting moves made by pieces removed from the board. If the grand total is even, the 'move' will not be altered; if odd it will be."

Although there are hundreds of different modes of effecting a treble exchange, there are only 16 main governing conditions, and in each instance one of these will be employed. They are as follows : — First, an exchange pure and simple, in which an even number of men are removed from, each system, with no waiting moves, and your own turn to play after the exchange. Second, ditto; but your opponent's turn to play afterwards. The third and fourth are similar to the first and second respectively, except that an odd mmiber of men is removed from each system. The conditions are similar in the fifth, sixth, seventh, and eighth respectively, except that in each instance there is one waiting move. In the next four styles there are two waiting moves, and in the last four there are three waiting moves. It would occupy too much space to give examples of each, but players can easily set up examples for themselves. When we understand the principles governing the alterations of the move, we might further simplify the rulei by leaving out all even numbers. For instance, if the number of men removed from, one system is even, or if there is an even number of waiting moves, they need not be included in our calculation, as even numbers do not alter tho "move" ; it is only necessary, therefore, to co\mt the odd numbers, but in the example given below we will apply the rule in its entirety. Black moves first in all examples.

No. 1. Black men on 1, 6, 9, 15, 19. White men on 30, 29, 28, 26, 17. "White has the "move," and we wish ©1 decide what effect the exchange by 9 14, 17 10, 19 23. 26 19, 15 24, 28 19, 6 24 will have on it. We will first count the mimber of men. which will be removed from one of the systems. Take the White system, and we find that the man on 15 is the only one affected ; there are no waiting moves, but iff will be White's turn to play after the exchange, and we must, therefore, add one to the man removed, which makes the total 2, which is an even number. White will thus retain the "move. No. 2. Black men on 1, 2, 5, 9, 13. White men on 31, 29, 23, 22. 15. Black has the move, and if we exchange 13 17, 22 6, 1 26, 31 22, what will the result be? There are no waiting moves, and it will be Black's turn to play afterwards, so we need only count the pieces removed from, one system. There are two men removed from tho Black system, those on 1 and 9. The number b&ing even, Black retains the "move." No. 3. Black on 1, 2, 6, 10, 11. White men on 29, 27, 20, 18, 12. Wiha-t effect will the exchange by 11 16, 20 11 2 7, 11 2, 1 5, 2 9, 5 32 have on the "move,"' which is in possession of White at present? There is one piece (that on 6) removed from, -the -Wliite system, one waiting move (1 5), and White's turn to play afterwards. Our total is, therefore, three, which, is an odd number. Black gains the "move." No. 4. Exactly the same position as No. 3, except that a 'black man is on 7 instead of 2. Black haa the "move," and by exchanging 11 16, etc., he retains it, as our total is even, there being two men removed from the White system, plus one waiting move, plus White's move. No. 5. Black men on 2, 7, 14, 16, king 13. White men on 29, 28, 27, 26, king 3. Black has the "move," and retains it by playing- 16 20, as our total is even, there being three men removed from the Black system, plus one waiting move. No 6. Black men on 2, 7, 8. 14, king 6. White men on 32, 29, 27, 26, 12. White has the "move." If Black plays 6 9 and 9 13, White will retain the "move," our total being even. There are three men removed from the Black system, plus the two waiting moves, plus White's move afterwards. No. 7. Black men on 5. 7, 8, 14, king 9. Whit© men on 32, 29, 27, 26. 12. Black has the "move," but will lose it if? he plays 9 18, 12 3, 13 17. 3 10, 17 13, 10 17, 13 24. as we have an odd total — three men removed from the Black system, plus three waiting moves, plus White's move. The above examples are sufficient to show the detailed method of calculating the effect of a treble exchange on the "move." When, ■ihe principles are understood", the simpler methods may be adopted. (Concluded.)