After the crossword is solved (completed solution below) there are six clues that specify the turn order of the pieces, which is QU, KN, BI, PA, KI, RO. There are also six squares where, in order to make the across clue work, one of these six two-letter abbreviations is inserted. The six pieces are chess pieces according to their abbreviations. As the flavortext says, they then take four turns each, in order. On each turn, the appropriate abbreviation moves to a new square according to legal chess rules, under the constraint that if its new square's letter is replaced by its abbreviation, the across answer is still a word. For example, the first move is the queen (QU) which moves straight up to 55A, making BIZ into QUIZ. The second grid below shows all moves of all pieces, where the pieces are colored according to rainbow order and the order of moves is according to shading.
Each piece's moves trace a letter; the letters in turn order are PENCIL, which is the answer.
1 D | 2 E | 3 N | I | 4 A/RO | 5 D | 6 B | 7 L | 8 A | 9 C | K | 10 P | 11 A | 12 N | 13 T | 14 H | 15 E | 16 R | ||||||
17 E | 18 L | O | P | E | 19 T | 20 M | O | 21 I | O | U | S | 22 A | T | A | R | A | X | I | 23 A | ||||
24 M | E | R | I | T | 25 L | A | N | 26 A | L | I | 27 A | S | 28 P | A | N | I | C | S | |||||
29 U | N | I | T | 30 A | L | U | 31 M | 32 A | N | D | 33 P | S | 34 E | M | O | T | E | S | |||||
35 C | O | 36 M | 37 N | A | T | I | 38 O | N | 39 A | P | E | V | 40 D | U | |||||||||
41 M | A | R | T | Y | 42 S | P | A | 43 B | I | N | 44 B | E | 45 G | R | |||||||||
46 A | 47 R | 48 A | E/BI | C | 49 I | S | 50 C | U | L | 51 T | 52 B | A | G | 53 E | U | R | O | 54 P | E | ||||
55 B | I | Z | 56 B | 57 A | S | I | 58 E | 59 S | Y | R | I | A | 60 E | 61 D | D | Y | 62 E | A | R | ||||
63 E | D | I | 64 T | E | D | 65 A | A | 66 S | 67 S | I | 68 D | R | A | G | O | 69 N | S | ||||||
70 M | O | T | S | 71 S | T | 72 A | T | 73 S | 74 I | R | 75 S | E | N | A | T | 76 E | |||||||
77 H | U | G | H | 78 S | I | R | I | 79 W | A | R | M | 80 T | H | 81 E | T | O | N | ||||||
82 E | T | A | 83 F | L | E | A | 84 C | O | N | S | 85 E/PA | I | 86 R | A | |||||||||
87 R | H | E | 88 A | 89 O | O | R | T | 90 A | R | T | 91 A | N | A | 92 T | 93 H | 94 E | M | 95 A | |||||
96 F | 97 L | O | W | 98 F | 99 E | R | M | A | 100 T | 101 A | G | 102 R | I | G | E | L | |||||||
103 R | E | T | I | 104 N | O | L | 105 E | L | 106 F | 107 N | A | P | O | L | I | ||||||||
108 W | I | G | 109 N | O | R | S | 110 E | 111 D | A | R | 112 A/KN | E | S | S | Q | ||||||||
113 P | A | C | I | N | G | 114 D | I | R | 115 A | 116 C | 117 R | A | V | E | 118 Q | U | |||||||
119 S | A | O | 120 N | A | S | A | 121 N | O | D | 122 D | U | O | |||||||||||
123 S | 124 W | A | N | 125 E | 126 S | 127 T | 128 O | S | S | 129 K | I | T | 130 E | A | T | ||||||||
131 C | A | R | B | 132 A/KI | T | E | S | 133 R | E | I | 134 N | 135 I | D | O | 136 B | A | R | ||||||
137 P | O | I | 138 N | C | A | R | E | 139 E | R | G | O | 140 B | E | E | 141 A | U | N | T | |||||
142 A | P | T | 143 E | O | L | I | T | 144 H | 145 S | N | O | 146 K | E | 147 D | 148 O | T | S | ||||||
149 C | H | E | 150 C | R | E | A | S | E | 151 R | 152 S | N | I | T | 153 N | O | T | |||||||
154 T/QU | O | 155 K | N | 156 L | E | T | O | 157 O | P | S |
1 D | 2 E | 3 N | I | 4 RO | 5 D | 6 B | 7 L | 8 A | 9 C | K | 10 P | 11 A | 12 N | 13 T | 14 H | 15 E | 16 R | ||||||
17 E | 18 L | O | P | E | 19 T | 20 M | O | 21 I | O | U | S | 22 A | T | A | R | A | X | I | 23 A | ||||
24 M | E | R | I | T | 25 RO | BI | N | 26 A | L | I | 27 BI | S | 28 P | A | N | I | C | S | |||||
29 U | N | I | T | 30 A | L | U | 31 M | 32 A | N | D | 33 P | S | 34 E | M | O | T | E | S | |||||
35 C | O | 36 M | BI | 37 N | A | T | I | 38 O | N | 39 A | P | E | V | 40 D | U | ||||||||
41 M | A | R | T | Y | 42 S | P | A | 43 B | I | N | 44 B | E | 45 G | R | |||||||||
46 A | 47 R | 48 A | BI | C | 49 I | S | 50 C | U | BI | 51 T | 52 B | A | G | 53 E | U | R | O | 54 P | E | ||||
55 QU | I | Z | 56 B | 57 A | RO | QU | 58 E | 59 S | Y | R | I | A | 60 PA | 61 RO | D | Y | 62 RO | A | R | ||||
63 E | D | I | 64 T | E | D | 65 A | A | 66 S | 67 S | I | 68 PA | R | A | G | O | 69 N | S | ||||||
70 M | O | T | S | 71 S | QU | 72 A | T | 73 S | 74 PA | R | 75 S | E | N | A | T | 76 E | |||||||
77 H | U | G | H | 78 S | I | R | I | 79 W | A | R | PA | 80 T | H | 81 E | T | O | N | ||||||
82 E | T | A | 83 F | L | E | A | 84 C | O | N | S | 85 PA | I | 86 R | A | |||||||||
87 R | H | E | 88 A | 89 O | O | R | T | 90 A | R | T | 91 A | N | A | 92 T | 93 H | 94 E | M | 95 A | |||||
96 F | 97 L | O | W | 98 F | 99 E | R | M | A | 100 T | 101 A | G | 102 R | I | G | E | L | |||||||
103 R | E | T | I | 104 N | O | L | 105 E | L | 106 F | 107 N | A | P | O | L | I | ||||||||
108 W | I | KI | 109 N | O | R | S | 110 E | 111 D | A | R | 112 KN | E | S | S | Q | ||||||||
113 QU | A | C | KI | N | G | 114 D | I | R | 115 A | 116 C | 117 KN | A | V | E | 118 Q | U | |||||||
119 S | A | KI | 120 N | A | S | A | 121 N | O | D | 122 D | U | O | |||||||||||
123 S | 124 W | A | N | KI | 125 E | 126 S | 127 T | 128 O | S | S | 129 KN | I | T | 130 E | A | T | |||||||
131 C | A | R | B | 132 KI | T | E | S | 133 R | E | I | 134 N | 135 I | D | O | 136 B | A | R | ||||||
137 P | O | I | 138 N | C | A | R | E | 139 E | R | G | O | 140 KN | E | E | 141 A | U | N | T | |||||
142 A | P | T | 143 E | O | L | I | T | 144 H | 145 S | N | O | 146 K | E | 147 KN | 148 O | T | S | ||||||
149 C | H | E | 150 C | R | E | A | S | E | 151 R | 152 S | N | I | T | 153 N | O | T | |||||||
154 QU | O | 155 K | N | 156 L | E | T | O | 157 O | P | S |