CHUNITHM x Iyowa Collaboration Returns September 25 With Returning Characters and a New Stage Background

CHUNITHM is bringing back its collaboration with Vocaloid producer Iyowa (いよわ). SEGA has confirmed that the Iyowa event map will return from September 25 through November 11, 2026, giving players another opportunity to obtain characters previously available during the original collaboration.

This revival is not simply reopening the old content. A new map is being added with a stage background as its reward, the associated CHUNITHM Quest is returning, and Kyu-kurarin (きゅうくらりん) will receive a new ULTIMA chart on the same day.

Quick Summary

• Game: CHUNITHM Mate
• Series: CHUNITHM
• Official website operator: SEGA Fave
• Collaborator: Iyowa / いよわ
• Event type: revival collaboration event
• Announcement date: September 21, 2026
• Announcing account: CHUNITHM Official
• Official X: @chunithm
• Event begins: September 25, 2026
• Start day: Friday
• Event ends: November 11, 2026
• End day: Wednesday
• Iyowa event map: returning
• Additional map: yes
• New map reward: stage background
• Previous event characters: obtainable again
• CHUNITHM Quest: returning
• Quest reward: title earned through target character ranks
• Revival-related song: Kyu-kurarin
• Kyu-kurarin update: new ULTIMA chart
• ULTIMA date: September 25, 2026
• Original collaboration: 2024
• Original period: July 4–August 7, 2024
• Original event song: 1000-nen Ikiteru
• Original event song: Netsu Ijou
• Original event song: Apricot
• Original Platinum title: I ga Yowai kara Iyowa desu.
• Documented Iyowa-category characters: six
• Character: Kurari-chan
• Character: 1000-nen-chan
• Character: Imawa-san
• Character: Rico
• Character: Adachi Rei
• Character: Iyowa
• Stage background after the event: remains usable once obtained
• Another September 25 song: Kiki Kaitai
• Kiki Kaitai category: VARIETY
• Another September 25 song: LaVI-Bavellabion
• LaVI-Bavellabion category: POPS & ANIME
• New Iyowa song for the revival: not announced
• New Iyowa character: not announced in the main notice
• New revival PV/trailer: none found in the verified official material

Iyowa Collaboration Revival

The Event Map Returns From September 25 Through November 11

The revival begins on September 25, 2026 and remains available until November 11, 2026. During that period, the Iyowa collaboration map returns to CHUNITHM.

For players who missed the original 2024 event, the most important feature is the opportunity to obtain its character rewards again.

SEGA specifically highlights this point in the current announcement, inviting players who failed to collect the characters during the previous event to use the revival as another chance.

The in-game progression continues to revolve around event maps, while the new announcement primarily emphasizes returning characters and the additional map.

A New Map Adds a Stage Background Reward

The key difference from a straightforward rerun is the addition of a new map to the Iyowa event.

Progressing through the additional map allows players to obtain a stage background. The official news post also states that the reward can continue to be used after the event period ends once it has been acquired.

The stage background is the clearest newly announced cosmetic reward for the 2026 revival. The main notice does not introduce a new Iyowa character alongside the extra map.

The revival therefore combines another opportunity to collect past rewards with a new incentive for players who already completed the 2024 collaboration.

Kyu-kurarin Receives an ULTIMA Chart

The revival also coincides with a new ULTIMA chart for Kyu-kurarin (きゅうくらりん).

ULTIMA provides an additional chart for an existing CHUNITHM song rather than treating it as an entirely new track. In this case, the September update specifically announces the ULTIMA version rather than presenting Kyu-kurarin itself as a new song.

The chart becomes available on September 25, the same day the Iyowa revival begins.

That gives returning players fresh rhythm-game content even if they previously finished the original event map and collected its characters.

The Original 2024 Collaboration Added Three Iyowa Songs

The first Iyowa collaboration ran from July 4 through August 7, 2024.

Three Iyowa songs were added alongside that event:

• 1000年生きてる (1000-nen Ikiteru)
• 熱異常 (Netsu Ijou)
• アプリコット (Apricot)

The original map also featured characters connected to Iyowa's works. Documented event data lists Kurari-chan, 1000-nen-chan, Imawa-san, Rico, Adachi Rei, and Iyowa as the six characters in the collaboration category.

Certain progression areas were tied to collaboration songs. 1000-nen Ikiteru was connected with the 1000-nen-chan area, Apricot with Rico, and Netsu Ijou with Adachi Rei.

The original CHUNITHM Quest also awarded the Platinum title 「胃が弱いからいよわです。」, referencing the origin of Iyowa's producer name.

The CHUNITHM Quest Is Returning as Well

Alongside the event map, the collaboration's CHUNITHM Quest is being reactivated.

The quest uses the ranks of eligible target characters as progression. The 2026 official notice confirms that raising those ranks during the event period allows players to obtain a title.

Game Ad

Anna - Chapter 2

Event documentation for the original Iyowa quest lists six eligible characters and a combined-rank requirement for its Platinum reward.

That means returning characters serve more than a collection purpose during the revival, as raising them also contributes toward the accompanying quest.

Two Other Songs Arrive in the September 25 Update

The September 25 update contains more than the Iyowa content.

SEGA is also adding Kiki Kaitai (奇々解体) to the VARIETY category and LaVI-Bavellabion to POPS & ANIME on the same date.

Both songs appear in the same official news post, but they are not presented as Iyowa collaboration tracks. Keeping that distinction clear prevents general CHUNITHM additions from being mistaken for new material in the Iyowa package.

The Iyowa-specific update consists of the returning event map, the additional stage-background map, the returning quest, the ability to obtain previous characters again, and the new ULTIMA chart for Kyu-kurarin.

Why This Matters

1) Players who missed the 2024 event get another chance

Characters that were previously tied to the collaboration map can once again be obtained during the revival.

2) Returning players still receive something new

The additional map and its stage background give previous participants a reason to revisit the event.

3) Kyu-kurarin gains a fresh gameplay challenge

The ULTIMA chart expands Iyowa-related rhythm content without requiring an entirely new song.

4) The original event structure remains relevant

Character maps and the returning CHUNITHM Quest remain central to progression rather than the revival functioning as a simple song rerelease.

Game and Event Information

For now, the additional important information currently known includes:

• the revival was announced by the official CHUNITHM account on September 21, 2026
• the event runs from September 25 through November 11, 2026
• it revives the 2024 Iyowa collaboration
• the Iyowa map returns during the event
• a new map is being added to the Iyowa map set
• the additional map rewards a stage background
• the obtained stage background remains usable after the event ends
• characters from the previous event can be obtained again
• the official notice does not announce a new Iyowa character
• the CHUNITHM Quest also returns during the revival
• eligible character ranks contribute toward the quest reward
• the original quest awarded the Platinum title 「胃が弱いからいよわです。」
• original event data lists six characters in the Iyowa category
• Kurari-chan is one of the character rewards
• 1000-nen-chan is one of the character rewards
• Imawa-san is one of the character rewards
• Rico is one of the character rewards
• Adachi Rei is one of the character rewards
• Iyowa is also listed as a character reward
• the original collaboration ran from July 4 through August 7, 2024
• 1000-nen Ikiteru was added with the original collaboration
• Netsu Ijou was added with the original collaboration
• Apricot was added with the original collaboration
• Kyu-kurarin receives an ULTIMA chart on September 25, 2026
• Kyu-kurarin itself is not announced as a new song in this update
• the 2026 notice does not announce a new Iyowa song
• Kiki Kaitai enters the VARIETY category on the same date
• LaVI-Bavellabion enters POPS & ANIME on the same date
• those two songs are part of the wider September 25 update rather than the Iyowa collaboration announcement
• no new revival trailer or PV was found in the verified official material
• this article therefore does not use a video embed or video screenshot grid
• the main event visual comes from the official CHUNITHM announcement
• the current official Japanese service uses the CHUNITHM Mate branding
• the official Japanese website is operated by SEGA Fave
• official game information is available through the CHUNITHM Official Website
• official updates are available through CHUNITHM Official X
• the main announcement is available through the Iyowa Revival Official X Post
• full revival details are available through the September 25 Official Update
• original event details are available through the Original 2024 Iyowa Collaboration

Closing

The Iyowa revival gives CHUNITHM players another chance to collect characters from the 2024 event while adding new reasons to return through the stage background and Kyu-kurarin's ULTIMA chart. The event runs from September 25 through November 11, 2026.

For now, SEGA has not announced a new Iyowa character or an entirely new Iyowa song specifically for the revival. The confirmed additions instead center on the extra map, stage background and Kyu-kurarin ULTIMA chart.