by The Osomatsu-san 10th anniversary celebration has reached another memorable milestone.
To mark the conclusion of the franchise’s 10th-anniversary year, a brand-new illustration featuring the six Matsuno brothers planting a “commemorative pine tree” has been unveiled. The visual captures the six brothers together as they take part in a symbolic planting project designed to express gratitude to fans who have supported Osomatsu-san for the past decade.
The newly drawn illustration was created by Eiji Yasuhiko, who served as character designer for the anime’s third and fourth seasons.
But the illustration is more than just an anniversary image.
A real-world commemorative tree-planting project has also been launched in cooperation with Mitaka City in Tokyo, where Studio Pierrot, the animation production company behind Osomatsu-san, is based. Details about the actual planting event and location are scheduled to be announced later.
The project gives the 10th-anniversary celebrations a lasting physical symbol—one that can continue growing long after the anniversary campaign itself ends.
A New Visual Marks the End of the 10th-Anniversary Year
The newly released visual shows Osomatsu, Karamatsu, Choromatsu, Ichimatsu, Jyushimatsu, and Todomatsu together as they plant the commemorative pine tree.
The image was created specifically as the final visual of the 10th anniversary year.
According to the official announcement, the illustration expresses two central messages: gratitude to everyone who has supported Osomatsu-san throughout its 10-year history and a wish that the franchise will continue to be loved for many years to come.
The choice of a pine tree is particularly appropriate for the project.
The Japanese title Osomatsu-san is closely associated with the Matsuno brothers, whose family name contains the character “matsu,” meaning pine. As a result, planting a “commemorative pine” creates a direct connection between the franchise and its six central characters.
In other words, the tree is not simply an anniversary decoration.
It serves as a symbolic representation of the franchise itself.
Eiji Yasuhiko Creates the Anniversary Illustration
The new artwork was created by Eiji Yasuhiko, who worked as a character designer for Osomatsu-san Seasons 3 and 4.
His involvement gives the final anniversary visual a direct connection to the franchise’s more recent anime production.
The six brothers are depicted together in a scene that feels less like a traditional promotional illustration and more like a message of thanks to the audience.
Rather than focusing on one particular character, the artwork brings all six brothers together, emphasizing the group identity that has remained at the center of Osomatsu-san throughout its television history.
The official anniversary site describes the illustration as a final visual for the 10th-anniversary year and specifically connects it to the franchise’s desire to remain loved in the future.
Osomatsu-san’s 10th Anniversary Began in 2025
There is an important timeline detail for fans.
The original Osomatsu-san television anime began airing in 2015, and the franchise officially reached its 10th anniversary on October 6, 2025.
The anniversary celebrations then continued through 2026 with a large collection of events, collaborations, special merchandise, fan campaigns, and other projects.
The official 10th-anniversary website describes the franchise’s journey as beginning in 2015, when the six grown-up brothers returned as Osomatsu-san and created a major cultural impact in Japan.
Therefore, the October 6, 2026 announcement should be understood as a finale to the 10th-anniversary year of celebrations, rather than the date on which the franchise itself first reached 10 years.
What Is Osomatsu-san?
For newcomers, Osomatsu-san is a comedy anime based on Osomatsu-kun, the classic manga created by legendary manga artist Fujio Akatsuka.
The modern Osomatsu-san series reimagines the famous sextuplets as adults.
The six brothers are:
- Osomatsu — the eldest brother
- Karamatsu — the self-proclaimed cool guy
- Choromatsu — the relatively serious and practical brother
- Ichimatsu — the quiet and eccentric brother
- Jyushimatsu — the energetic and unpredictable brother
- Todomatsu — the youngest and socially savvy brother
Although they are identical sextuplets, each brother has a completely different personality.
That difference is one of the main sources of the show’s comedy.
Why the Pine Tree Is a Perfect Symbol
The “commemorative pine” concept works especially well because the word matsu is part of the brothers’ family name.
The six brothers are the Matsuno family, making the pine tree a playful but meaningful visual representation of Osomatsu-san.
The project also gives fans something tangible to associate with the anniversary.
Anime anniversaries often produce limited-edition illustrations, merchandise, concerts, exhibitions, or special episodes. A tree, however, is different.
A tree grows.
That makes it a fitting symbol for the franchise’s hope that Osomatsu-san will continue to be enjoyed by future generations.
The official announcement specifically says the project is intended to express gratitude for the past 10 years while wishing for the franchise to be loved for many years to come.
Osomatsu-san and Mitaka City Join Forces
The real-world planting project is being carried out in cooperation with Mitaka City, Tokyo.
This connection exists because Studio Pierrot, the animation studio responsible for producing Osomatsu-san, is based in Mitaka.
The collaboration therefore creates a direct connection between the anime franchise and the city associated with its production.
At present, the official announcement has not revealed all details about the actual planting ceremony or the exact location.
Instead, fans have been told that additional information will be announced at a later date.
This leaves fans waiting to learn where the commemorative pine will be planted and how the public will be able to participate or visit it.
The Six Brothers Continue Their Anniversary Celebration
The tree-planting project is only one part of a much larger 10th-anniversary campaign.
Throughout 2025 and 2026, Osomatsu-san celebrated its milestone with a wide range of activities.
The official anniversary website lists several major projects, including:
- A special Osomatsu-san × Gintama collaboration
- The 10th ANNIVERSARY OSOMATSUSAN SPECIAL 6DAYS event
- Collaborations with Keroro Gunso
- A collaboration with Welcome to Demon School! Iruma-kun
- The “6-Station Network Thank You Journey”
- The Osomatsu-san General Election
- The Daima-tsu no Ichi merchandise event
- The second Matsu Main Assembly
- A special anniversary screening
- The revival of the Miyu Irino Goods Development Room
These projects helped make the anniversary much more than a single event.
The Osomatsu-san × Gintama Collaboration
One of the biggest recent anniversary collaborations was with another hugely popular comedy anime, Gintama.
The official anniversary site announced the collaboration as the project that would serve as the finale of the 10th-anniversary collaboration lineup.
A special collaboration visual was unveiled, along with plans for original merchandise.
The pairing is particularly fitting because both Osomatsu-san and Gintama are known for their irreverent humor, chaotic characters, parody, and willingness to break conventional anime storytelling rules.
For longtime fans, the collaboration became one of the highlights of the anniversary year.
“6-Station Network Thank You Journey” Reaches Its Finale
Another major anniversary project was the “6-Station Network Thank You Journey.”
The project sent the six brothers to different regions connected to the six television networks that broadcast the series.
The final stop was Okayama, where Ichimatsu and voice actor Jun Fukuyama appeared at an event in August 2026.
The event included a talk show, a greeting with the local mascot Nanana, and limited-edition postcards featuring a special collaboration illustration.
The project gave Osomatsu-san an opportunity to interact directly with fans around Japan rather than limiting the anniversary celebration to Tokyo.
Osomatsu-san General Election Also Became Part of the Anniversary
Fans were also invited to participate in an Osomatsu-san General Election.
The project allowed fans to vote in multiple categories based on memorable moments and characters from the franchise’s 10-year history.
The character category was won by Karamatsu.
As a result, one of the promised rewards was a digital photo book titled “Matsuno Karamatsu Photo Book 2026.”
The official anniversary site made the photo book available free of charge during its designated release period.
The voting project demonstrated how strongly fan participation has remained connected to the franchise even a decade after the modern anime began.
Miyu Irino Goods Development Room Returns
Another major anniversary project is the revival of the “Miyu Irino Goods Development Room.”
The project returned as part of the 10th-anniversary celebrations, with voice actor Miyu Irino, who voices Todomatsu, involved in the development of original merchandise.
The third installment of the project is a collaboration with denim brand DENHAM.
The collaboration includes several fashion and lifestyle items featuring Osomatsu-san-inspired designs.
Osomatsu-san × DENHAM Merchandise
The DENHAM collaboration includes:
- CROSSBACK OSOMATSU R men’s denim
- KEIRA OSOMATSU R women’s denim
- EMMA L SKIRT OSOMATSU R women’s denim skirt
- DNHM SCISSOR TOTE OSOMATSU
- DNHM OSOMATSU BANDANA, available in six designs
The official information lists the women’s denim at ¥38,500, the denim skirt at ¥36,300, the men’s denim at ¥44,000, the tote bag at ¥7,700, and the bandanas at ¥2,200 each, including tax.
The women’s denim, skirt, tote, and bandanas were initially offered through the official fan club’s advance order period, while the men’s denim was planned for a later release.
The official anniversary site announced on October 6 that the collaboration goods had entered their next sales stage.
A BE@RBRICK Collaboration Is Also Coming
The Osomatsu-san × DENHAM project has another major component.
In August 2026, the official anniversary site announced a triple collaboration between Osomatsu-san, DENHAM, and BE@RBRICK.
The project will feature an Osomatsu BE@RBRICK collectible.
The detailed release information and sales timing were initially announced as forthcoming.
For collectors, this could become one of the more notable pieces of merchandise connected to the 10th-anniversary campaign.
The Fourth Anime Season Was Also Part of the Anniversary Era
The anniversary celebration has also coincided with the continuation of the television anime itself.
Osomatsu-san Season 4 began broadcasting in July 2025 and eventually reached its final episode in 2026.
The official site later announced a special theatrical screening of Episode 13, along with the 10th ANNIVERSARY OSOMATSUSAN SPECIAL 6DAYS event.
The 10th anniversary therefore celebrated not only the original 2015 series but also the franchise’s continued ability to produce new television content a decade later.
Why Osomatsu-san Has Remained Popular for 10 Years
One reason Osomatsu-san has survived for a decade is the flexibility of its characters.
The six brothers can appear in almost any situation.
They can be unemployed adults, fantasy characters, office workers, idols, historical figures, or exaggerated versions of themselves.
Their personalities are recognizable enough that fans can immediately understand the joke, while their flexibility allows creators to constantly place them in new situations.
This has also made Osomatsu-san particularly suitable for collaborations.
The characters can easily be redesigned around another franchise, brand, event, or theme without losing their identity.
The Six Brothers Have Become a Major Anime Brand
The modern Osomatsu-san series has grown beyond television.
Over the years, the six brothers have appeared in:
- Anime series
- Films
- Stage productions
- Live events
- Merchandise
- Fashion collaborations
- Advertising campaigns
- Special exhibitions
- Cross-franchise collaborations
The official 10th-anniversary site itself describes the franchise as expanding across television anime, theatrical films, stage productions, and live-action projects.
That broad presence explains why the anniversary campaign has been able to continue for such a long period.
A Tree That Represents the Future
The commemorative pine tree is arguably one of the most fitting ways to conclude the 10th-anniversary celebrations.
A limited-edition product eventually disappears.
A special illustration becomes part of the franchise’s archive.
An event eventually ends.
But a tree can continue growing.
That makes the project a symbolic representation of the franchise’s future.
The six brothers have spent the past 10 years entertaining fans through countless ridiculous situations. Now, their latest anniversary visual shows them doing something unexpectedly wholesome: planting a tree together.
It is a simple concept, but it carries a clear message.
The creators want Osomatsu-san to continue growing alongside its audience.
What Happens Next for Osomatsu-san?
The conclusion of the 10th-anniversary year does not necessarily mean the end of Osomatsu-san.
In fact, comments from the franchise’s cast suggest that the characters may continue appearing in future projects.
The official anniversary site includes comments from the six brothers’ voice cast celebrating the milestone and expressing gratitude to fans.
Notably, Takahiro Sakurai, the voice of Osomatsu, referred to the possibility of continuing toward a potential sixth season, while also expressing his desire to keep the celebration going.
However, this should not be interpreted as an official announcement of Osomatsu-san Season 6.
For now, fans can simply enjoy the anniversary projects and wait for any future announcements.
The Osomatsu-san 10th anniversary is ending with a surprisingly meaningful image.
The six Matsuno brothers—Osomatsu, Karamatsu, Choromatsu, Ichimatsu, Jyushimatsu, and Todomatsu—are shown planting a commemorative pine tree, creating a visual that connects the characters directly to the meaning of their family name and to the future of the franchise.
Created by Eiji Yasuhiko, the character designer for Seasons 3 and 4, the illustration expresses gratitude to fans who have supported Osomatsu-san throughout its decade-long history and hopes that the series will continue to be loved for years to come.
The project becomes even more special because the fictional planting scene will be connected to a real tree-planting project with Mitaka City, where Studio Pierrot is based.
Although details about the actual planting ceremony have not yet been announced, the project gives the anniversary a lasting symbol that can continue to grow after the celebrations are over.
The finale of the anniversary year also comes after an extraordinary series of projects, including the Gintama collaboration, the six-station thank-you tour, fan elections, special events, the return of the Miyu Irino Goods Development Room, and the DENHAM fashion collaboration.
For longtime fans, the commemorative pine is therefore more than another piece of anniversary artwork.
It is a simple message from the franchise:
Ten years have passed, but the six brothers’ story does not have to stop growing.
And as the Osomatsu-san 10th-anniversary year comes to a close, fans now have another reason to look forward to whatever the six troublesome brothers do next.
