VII
Checkmate.—When the King is in check and has no power of escape—that is, the attacking piece cannot be captured, the King moved, or a piece interposed between the King and the attacking piece—it is “checkmate,” and the game is lost for his side. To escape from a double check the King must move, and if there is no square to which he can move the game is lost, though both the attacking pieces are en prise, for it is plain that if one be taken the check from the other yet remains.
The diagram on page 286 will help the student to understand these different checks.
In the first place let White play R to Q 2, and it is a direct check. The Black K cannot move out of check, as all the squares adjoining his present position are either guarded by White pieces, or blocked by Black ones; neither can the R be taken, for no Black piece attacks it. Black, however, has one move to parry the check, and that is by playing Q to Q 5, or interposing the Q as it is termed. Similarly, White can play Q to Q sq, again giving direct check, to which Black can again only reply Q to Q 5. Once more, White can play P to R 8, becoming a Q or a B and giving direct check, to which Black’s only reply is Q, Q Kt 2.
In the second place, if White play Kt to Q 2 he gives a discovered check; that is, by so moving his Kt he uncovers the attack of the Q upon the K, or, in other words, the Kt moving discovers the check by the Q. In reply to this move Black has again only one move, that being P to B 5 or interposing the P. If White play B R 7, Q 3, B 2, or Kt sq. there is again a discovered check, for the R now attacks the K. In reply to this Black has three lines of play, namely, K takes Kt (at K 3) which is left unguarded by the removal of the B, or by playing the Q either to K 4, or Kt 4 interposing. If the B had gone to Kt 6 the Q could only interpose at K 4; and if it had gone to Kt 4 or R 3 the K could not then capture the Kt, but, instead, could have moved to K 5 out of check.
In the third place if the B move to K 4 there is then given double check, for whilst the B now directly checks himself, by moving he has also discovered the check from the R, and the King to get out of this double attack must move. He has two lines of escape, one by capturing the Kt at K’s third, the other by capturing the attacking B.
In the fourth place let White play P K 4, and the K is in direct check; but it is now checkmate, for the K has no possible move out of check, and the checking Pawn cannot be taken. Again, let White play Kt, Kt 6, and he gives double check, for the Kt checks directly, and has also discovered the check by the Q. Once more this is checkmate, for the K has no possible move. It is true that the B could capture the attacking Kt, but then the Q still checks and the danger of mate has not been averted; similarly, the P could cover at B 5, but the attack from the Kt remains all the same. This aptly illustrates what I have already said as to the extra danger of a double check.