The really terrible battles in human history up until the modern era are two or three days long. A battle is generally something on a small enough area where if you can get above the fray and the dust and the commotion and the chaos, you can usually see the whole thing. You're better off referring to these things as 'operations' instead of battles. But it sure makes it less dramatic in the big picture sense and much harder to follow. In the small unit sense, it is as dramatic and horrifying as any encounter you'll find in the war, maybe worse.
When do spirit, tenacity, resilience and bravery cross into madness? When cities are incinerated? When suicide attacks become the norm? When atomic weapons are used? Japan's leaders test the limits of national endurance in the war's last year.