Hitori is a numerical puzzle created in Japan. Hitori is a 3x3 to 25x25 square field with each cell filled with either a number or a letter. No row or column can have more than one occurrence of any given number. The goal is to find the numbers that have been placed incorrectly and mark them black.

The black cells must to touch either horizontally or vertically, but there can be diagonally adjacent black cells. The cells that remain blank have to touch others, as well as any of the surfaces, and create a single area.

A left mouse click can be used to mark cells black. The cells that duplicate and, therefore, were filled incorrectly are highlighted red. The red color for duplicates in a single row is brighter than the one for duplicates in the same column. The right click can also be used to mark the cells that are most likely not to be black. However, this mark is only supplementary and does not affect the solution check.

To check whether Hitori has been solved correctly, please click the corresponding button. Mistakes are marked in red, whereas the pink color shows the isolated areas. The number of black cells must not exceed the one specified in the problem; otherwise, the check button will become inactive.

7
8
x1
2023-02-08 07:00
00:38
17%
8x8
15
34
38
x1
2023-01-31 09:28
00:42
22%
9x9
21
27
29
x1
2023-01-26 15:41
00:39
17%
9x9
22
18 1
22
x1
2023-02-07 07:01
00:33
22%
8x8
16
28 2
34
x1
2023-01-26 01:37
00:37
20%
6x6
10
24
29
x2
2023-01-18 06:21
06:21
49%
21x21
66
36
40
x1
2023-01-14 13:46
00:06
2%
4x4
5
35
40
x1
2023-01-12 22:11
00:10
2%
5x5
7
35
36
x1
2023-01-11 11:03
00:14
5%
4x4
4
29
32
x1
2023-01-11 11:27
00:28
14%
7x7
11
15 1
18
x2
2023-01-25 22:29
02:52
22%
19x19
54
27
28
x1
2023-01-14 18:00
00:09
0%
4x4
5
27
27
x1
2023-01-16 21:20
00:07
0%
4x4
5
15
17
x1
2023-01-18 22:44
01:31
23%
13x13
35
24
25
x1
2023-01-16 21:31
00:18
5%
6x6
10
23
25
x1
2023-01-14 09:04
01:08
15%
12x12
31
13
14
x2
2023-01-19 18:00
02:28
18%
17x17
45
21
21
x2
2023-01-12 17:08
01:59
20%
18x18
47
20
20
x1
2023-01-16 21:12
00:27
9%
7x7
14
22 1
26
x1
2023-01-12 00:32
01:22
20%
11x11
32
26 2
29
x1
2023-01-13 17:43
00:23
13%
7x7
13
24
26
x1
2023-01-10 00:55
01:38
12%
15x15
42
6 1
8
x1
2023-02-01 12:00
00:27
17%
9x9
22
24 1
28
x1
2023-01-10 22:14
00:51
28%
8x8
18
22 1
24
x3
2023-01-10 22:30
06:29
43%
25x25
91
14 1
15
x1
2023-01-16 21:40
02:46
27%
15x15
44
37 1
41
x1
2023-01-05 12:21
00:06
9%
4x4
4
31
33
x1
2023-01-05 18:56
00:06
6%
4x4
4
20
22
x1
2023-01-07 18:27
01:44
18%
15x15
43
17
19
x1
2023-01-05 18:37
01:23
10%
11x11
31
17 1
19
x2
2023-01-04 18:18
03:12
26%
20x20
53
28 1
31
x1
2022-12-25 10:21
00:35
18%
8x8
18
20 1
22
x1
2023-01-01 12:00
00:11
3%
5x5
7
25
28
x1
2022-12-20 21:00
00:17
7%
5x5
8
25
28
x1
2022-12-20 21:00
00:14
5%
6x6
7
29 1
33
x1
2022-12-17 18:00
00:08
4%
4x4
4