Golden Time Anime: How did Banri lose his memories?

Golden Time Anime has spent quite some time into the passage of time. Yet today we dare not from asking, how did Tada Banri lose his memories? Is his amnesia realistic?

Adjusting to college life is hard enough for most students, but ever since Banri Tada lost all his memories he's literally being haunted by the spirit

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Golden Time Anime: How did Banri lose his memories?

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Golden Time Anime: How did Banri lose his memories?

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