Ushiro no Shoumen Daare

Both are about children, set in World War 2  

Both anime are based on autobiographic novels telling a WW2 related story trough the eyes of a primary school aged child. Both in their first half show their daily life and play in a slice of life style. Thereafter, the tragic event ending this peaceful part and the resulting consequences differ in both stories. 

both animes talks about ww2 and childrens suffring in that time art is somehow similaire  

both series are about war but Ushiro no Shoumen Daare is less saδ 

Both tell stories of childhood during WW2. Both MCs are ~ 10 y/o chidren, in Ushiro a girl and in Gen a boy, whose families are in the middle of a cataclysmic envent (Tokyo firebombing in Ushiro, nuclear bomb on Hiroshima in Ken). In both, for the first half of the movie regular 1940s family life in Japan is shown. In Ushiro, it reaches pretty much slice of life grade. Both movies end on a high note and a "life must go on" message after the end of the war and horrific consequences for both kids' families. A key difference is that in Gen death and destruction happens on screen, whereas in Ushiro MC at no point is personally in the middle of war atrocities. This narrative stryle makes it more similar to Kono Sekai no Katasumi ni than to Gen, but the depiction of family life and MCs age is more similar with Gen. read more 

the two animes are very similar, gen and koichan's parents are burned to death and the two brothers stay alive, these two animes are like a copy of each other. 

Both are unagitated anti-war tragedies from the POV of a young girl. Violence and death only happens off-screen, the focus remains on their ordinary life which is increasingly influenced by indirect consequences of the war. Both blend blend of slice of life, history, and tragedy. The protagonist in "Who's Left Behind?" is younger (age 6-11 covered) than in "Corner of the World" (Older teen to young adult), yet their life within the family and overall biography is similar. These two movies are more similar than the other two big anti-war movies, Grave of the Fireflies and Barefoot Ken. The latter comes in 2nd closest. 

Similarities in narrative structure and focus, although Ushiro no Shoumen Daare focuses on a younger protagonist, and a less distinctive art style. 

They're both war movies based on real life people that adapt their lives into movie format. Both are focused on young girls, their lives, and their families both before and after World War II, both girls have to grow up fast and deal with tragedy in their own way in order to survive, and they both lose their families. Admittedly though, Who's Left Behind is stronger because it's more subtle, has better character development, the characters are more engaging and three dimensional, and there's very little conflict, and when there's actual death, it isn't explicit, making the movie far more chilling. It also has a bit more heart to it than Glass Rabbit. read more 

WWII period drama biographies by the same director exploring Japanese nationalism from a child's lens.