Illusion of a 7th Person (幻の7人目) or Septupletmatsu (七つ子松/7つ子松) is a name given to a specific type of drawing mistake in the Osomatsu-kun franchise, in which seven brothers may accidentally be depicted in a scene.


In the early manga and the black-and-white edition of the anime, there may be such occasional mistakes made.

Generally, the instances in the anime can be seen as:

  • Animation miscommunication when Osomatsu is talking or present off-screen, while six other brothers are shown
  • If six follow after one other person
  • In other cases, 7 brothers being outright shown in a shot and there being no plot explanation; a tanuki in disguise, a robot, or so on.

With the manga, this can be figured due to be a mistake when it came to Akatsuka and staff working against deadlines, or errors that they opted to keep for the humor value.

Less commonly, there may also be an Octupletmatsu (八つ子松/8つ子松) variation in which two boys are present when they shouldn't be in a similar vein to "Osomatsu appearing when six boys are already there", or other extras are outright seen (and there is no in-story explanation such as alien or Kansai doppelgangers).



The Master of Right and Left

  • Six other brothers are shown to hide in the construction pipes as they see Osomatsu off and get him to take their places at school.

The Nonsensical Town Sports Festival (frontispiece)

  • Seven Matsunos in total are in the illustration, though in one case it may be more for the sake of the gag and art (and one does not necessarily know who is who for each activity)

A Samurai's Thousand Tribulations

  • Osomatsu and Choromatsu come home to see their five other brothers (instead of four) studying homework. The extra then vanishes within the next panels, however.

A Trip to Space on an Empty Stomach

  • Six other brothers pop up and react in glee to Osomatsu announcing that he's got six tickets to outer space.

Who is that Mole Thief! (frontispiece)

  • Among the characters popping up out of the Whack-a-Mole game in this illustration, seven Matsunos can be counted in total.

1966 anime

There's the Shortcut


  • The number of Matsunos climbing the roof is already inconsistent between shots, either being four or six in total. After the boys tumble off the roof, Osomatsu shows up to tell them he's found a way to get past Iyami's house. However, we can see that six other brothers respond to him.

The Cutie who Moved Nearby


  • Six brothers can be seen with Totoko in reacting to Osomatsu's news about a new girl moving in next door, though the extra error boy vanishes in the following shots.

Iyami the Rude Guest


  • Though Karamatsu is rolled up in a futon and forgotten by the family for the rest of the skit, six brothers continued to be animated into some still or panning shots by mistake. However, the extra Matsuno does vanish by the time the family leave home and Karamatsu is seen trying to hop after them.

Promotional Sales War


  • Seven boys are shown in a close-up shot as they gather together to talk, with the seventh likely being a mistake of an extra animation loop/drawing not caught in time. He is not seen in the wider, far away shot.

Totoko-chan's New Years' Card


  • When the rest of the cast glare down at Chibita and are shown in a panning shot, it is shown that a seventh Matsuno is in there by mistake as well.

1988 anime

Beat the Aliens!


  • Six pairs of feet are shown to run downstairs when the parents panic over the missing furniture and household items. However, Osomatsu and Choromatsu have been abducted, and their alien doppelgangers are also not present in the house. The following shots correctly show the other four brothers, with no others about. Thus, an accidental, implied Octupletmatsu error had been briefly created on top of an in-story explanation for there being "extra" (but fake) boys.

Iyami's Fishy Beach House!


  • Osomatsu goes off to find a bathroom, but six brothers are shown in the following scene when the others are getting changed into swimwear. The extra boy does disappear however, when the boys see that the lockers are unable to be opened.
  • An outright seventh brother is shown (and even through Chibita's binoculars) when the sextuplets rejoice over having found mussel shells in the sand.

Next on notice for "Iyami, 40 Years Later-zansu" (seen at end of "Detective Iyami versus Phantom Thief Dayon!")

In this case, this mistake would have not been a Septupletmatsu error but another Octupletmatsu-type one had it not been caught in time for the episode's airing:

  • Eight middle-aged salaryman Matsunos can be seen walking out the door in the first shot of this preview, with there being two extra men before the bald Choromatsu is revealed. In the final product, the two extra men were removed from the loop and there are six Matsunos as there should be.


Aside from the intentional skit and character of Kamimatsu (and even Sanematsu's dream stint as a 7th brother), this series encountered an actual error involving the Octupletmatsu variation.

Pachinko Police

When Todomatsu is cornered by his brothers as the Pachinko Police, Osomatsu and Karamatsu (and Jyushimatsu) are accounted for elsewhere in the shot, while two unidentified Matsunos stand behind Ichimatsu and Choromatsu as additional police. This may have been due to a layout error and miscommunication, or a mistake in interpreting other police as sextuplets. In whatever case, there would be 8 Matsunos.

There may also even potentially be a ninth brother by error, as instead of Iyami, when Osomatsu and Karamatsu's group is shown from behind, another cop with short dark hair with a similar style is present.

Other Instances

Koredeiinoda "Sheeh!" Contest

The inline image banner contains 7 Matsuno boys performing the pose, rather than the expected amount.

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