September 9 Is Now Officially "Attack on Titan Day" in Japan

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September 9 is now officially Attack on Titan Day — and this year's celebration is built entirely around the number 99.

Kodansha has designated September 9 as the series' official commemorative day, marking the date Attack on Titan began serialization in 2009.

Why September 9

The manga began its original serialization on September 9, 2009, giving the series a fixed anniversary date to build future celebrations around.

The 99-Hour Free Campaign

Starting at 00:00 JST on September 9, 2026, the Magapoke app is making Chapters 1 through 99 free to read for 99 hours, ending at 02:59 JST on September 13.

The 99/99/September 9 motif ties the chapter count, the hour count, and the calendar date together for this first official celebration.

Other Commemorative Activities

Commemorative merchandise launches at Magazine Shop, and a special livestream is planned for September 9. Further details for both have not yet been announced.

What To Know

For long-time fans, the new official anniversary gives the series a recurring date that connects its original manga history with current fandom activity. The 99-hour reading campaign also makes the anniversary participatory rather than purely symbolic.

Japanese manga and anime franchises often build anniversaries around publication, broadcast or release dates. Turning one of those dates into an officially recognized commemorative day gives fans a fixed annual point to revisit the work together.

What Fans Are Saying

Original Japanese

Easy Japanese

9月9日が「進撃の巨人の日」になりました。9月9日から99時間、99話まで無料で読めます。