Clues Since the direction of the arrow is determined by the arrangement of the numbers, you may be able to identify the numbers that enter or do not enter from the arrangement of the arrows. The following is a main example, but light blue is the target square, red is the arrow that is the point, and gray is the number that can be identified. "Dotch" is can be achieved even in a single row, so it is easy to understand with a horizontal row. Number of single arrows. Either 1 or 9 is entered if there are only two single arrows in the empty squares of the row. Since D and F are the only empty squares with single arrows, D=1 facing 2 and F=9 not facing 2. Second square from the outside. If the second from the outside is a double arrow, the outermost and second numbers will be consecutive numbers. A=3or5, H=6or8. Second square from the outside (special form). If the second from the outside is an outward single arrow, there are two options. (1)The outermost is 2 and the second is 1. (2)The outermost is 8 and the second is 9. Since D3 is a left-handed arrow, A=2, B=1, and the right side is H=9, I=8. The second and third squares from the outside. If the second from the outside is an inward-facing single arrow and the third is an outward-facing single arrow, there are three options. (1)If the third number is other than 1 or 9, the third consecutive number is entered in the outermost and second numbers. (2)If the third number is 1, the outermost and second will be 2 and other numbers. (3)If the third number is 9, the outermost and second will be 8 and other numbers. In the case of the left side, AorB=2or4. In the case of the right side,there are four forms. (1)G=5 and I=4, (2)G=7 and I=8, (3)G=1 and I=2, (4)G=9 and I=8, but since AorB=2or4, G=7or9 and I=8. The second and third squares from the outside(special form). If the second from the outside is a double arrow and the third one is an outward single arrow, there are two options. (1)The third is 1 and the outermost and second are 2 or 3. (2)The third is 9 and the outermost and second are 7 or 8. Since F4 has a right arrow, G=1 and HorI=2or3, and on the left side C=9 and AorB=7or8. Continuous single arrows. If the single arrows are consecutive, the consecutive numbers of the block are not included in that block. If there is no double arrow in the row, five squares in the same direction will contain odd numbers, and four squares in the opposite direction will contain even numbers. Since either AorB is 2, odd numbers are entered in F to I, and even numbers are entered in A, B, D,and E. Every other number (1). If alternate numbers are facing each other with single arrows, there is a common sequence of numbers in the middle in the form of a double arrow. Since there is only E between C4 and G6, E=5. Every other number (2). If one of the alternate numbers is a single arrow, the opposite single arrow will contain the common consecutive numbers. In this form, double arrows to which the arrows are pointing do not contain common consecutive numbers. The single arrow pointing to both B4 and E6 is G and I, but if I is 5, H=6, which is a contradiction.Therefore, G=5. The result is the same even if B4 is a double arrow in the above figure. Single arrows facing each other. If the single arrows face each other without a double arrow in between, the numbers minus 2 and plus 2 cannot be entered. Same as the theory of every other number (1) above, 3 and 7 are not included in both C and D in the above diagram. Single arrows not facing each other. If the single arrows do not face each other, the numbers from minus 2 to plus 2 of the number cannot be entered. Since D5 is a left arrow, 4 and 6 are entered on the left side, so numbers 3 to 7 cannot be entered in F, which is not facing them. Therefore, the possible numbers are 1, 2, 8, and 9.