Eastern front involved many more millions of civilian deaths; some in Leningrad ate grass when there was no food. Plus in 1942-43 the winter was brutally cold, a much bigger factor than in the Pacific.
The only equivalent in terms of civilian misery in the Pacific might've been Manchuria and other places like that prior to the beginning of WW II.
That said, the Japanese were horrible to their prisoners.
Leningrad diary:
How agonizing the desire to eat was in the winter of 1941-1942. . . . In the city's empty streets there sometimes appeared trucks carrying the military. I would usually pull some tobacco out of my quilted jacket--if the truck stopped, I would offer it to the men in military overcoats: "Comrades! Have you got any twigs? Here is some tobacco for you!" They once tossed me a heap of aromatic pine branches. I gnawed on them all the way home. I totally devoured their tender bark and needles.
Yes, in the spring of 1942, grass was as much our salvation as were glue and leather straps. Those had to be prepared and then cooked, which required time and. . . fuel. But grass, it was growing everywhere--in the streets, in empty lots. It even poked through cracks in the asphalt.
As soon as the sun warmed up our devastated and starving Leningrad, green sprouts immediately started forcing their way through all the cracks. There were no more dogs in the city--all of them had been eaten. Children, looking more like old men, were not running around trampling down the grass, and besides, there were so few of them left in the city. The grass kept growing.
It was easy to cut heaps of new spring chamomile--its fluffy and aromatic little leaves went so well with the tender feather grass, which usually grows in the shade, close to houses. In the past it was used as food for birds. I made a delicious salad out of it to supplement the morning portion of our bread ration, which we received at 5:30 in the morning in a former bakery lit by two dim kerosene lamps. A portion of this grass and the remnants of the bread ration would be left for an evening meal.
And then there were the sticky little linden leaves of spring! You could eat them, or you could make soup out of them. And the sour leaves of barberries! And shepherd's purse! It says in science books that the latter helps to fight vitamin deficiency and scurvy. But there was not time for studying science books, whereas the feeling of hunger was always present. And my basket was filling up with all kinds of grasses.
How grateful I am to it, my dear, green, fresh, dewy grass! In the years since then, much has gradually disappeared from memory, but the memory of those bright spring mornings will never fade.