Reddit reviews Soldiers Of The Sun: The Rise and Fall of the Imperial Japanese Army

Yes, I've read it. My answer was for the army as whole, and it's doctrine.

My answer was based mostly on these books:

http://www.amazon.com/Eagle-Against-Sun-American-Japan/dp/0394741013/ref=sr_1_1?s=books&ie=UTF8&qid=1369281149&sr=1-1&keywords=eagle+against+the+sun

http://www.amazon.com/Soldiers-Sun-Rise-Imperial-Japanese/dp/0679753036

http://www.amazon.com/Fighting-Techniques-Japanese-Infantryman-1941-1945/dp/0760311455/ref=sr_1_2?s=books&ie=UTF8&qid=1369281120&sr=1-2&keywords=fighting+techniques+of+a+japanese

http://books.google.com/books/about/Warriors_of_the_rising_sun.html?id=wkHyjjbv-yEC

http://www.amazon.com/Path-Infinite-Sorrow-Japanese-Kokoda/dp/174237591X/ref=sr_1_1?s=books&ie=UTF8&qid=1369281290&sr=1-1&keywords=the+path+of+infinite+sorrow

I also left out the days of leave, vacations, holidays, low pay rate, sake rations, and lots of other things that might actually be "fun."

The Rape of Nanking seems fairly easy Here and Here, though I don't know about the Soldiers of the Sun

edit: also available
I will say my library doesn't have Soldiers of the Sun but does have Rape of Nanking.

Given the lack of living survivors I doubt you'll find an answer.

However, during a period when I had no internet, I came upon this book that shed some light the atrocities (mind you, guy has a JPN wife, so take it with a grain of salt).

http://www.amazon.com/dp/0679753036/ref=wp_dp_3