It happened during the "We Remember" part of the Olympic Closing Ceremony, dedicated to the souls of the departed, when in the shots of the
Nishimonai Bon Odori (西馬音内盆踊り) dance it was possible to spot the Oda mon over the stage of the musicians--
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I tried to investigate immediately, but it doesn't look like Akita is hosting some ancestors of the Oda clan-- The only reference I found referred to
the position of "Akita Jonosuke" (秋田城介) which was held by Nobutada starting November 1575.