As for whether there are war criminals that escaped punishment, I think they have to live every day of their lives knowing that hundreds of thousands of japanese men, women and children payed for their sins at Hiroshima and Nagasaki..
They will have to live with that secret guilt until the day they die, and their survivors, family members, descendants, those who know what their husband, father, uncle, grandfather did during the war, will also have to live with it.
Additionally, we are living in the beginning of what is being called the "information age"..
There will come a time when any japanese citizen can enter his/her grandfather's name on Google or some other search engine, and they will find that name listed as being an officer or crewman on some vessel in WW2, and find accounts of the murders performed by that vessel's crew members.
They will then know not only what their grandfather did in the war, but that everyone in the world with a computer terminal can easily find out what they did in the war.
How disgraceful will that be, when your grandpa's war crimes are a matter of public record on the world-wide web?
For all the world to see?
I cannot begin to imagine the humiliation those descendants will feel.
Those that escape prosecution will suffer the greatest punishment of all for their culture.
The public disgrace and humiliation of his entire family line.
Same with a lot of Americans over slavery and not upholding agreements with Amerindian tribes.
And for both Americans and the Japanese, an unwillingness to acknowledge the unflattering parts of your histories just increases the chances that you'll repeat those atrocities you have swept under the rug.
The shrine is Yazakuni [?], and among the war dead honored there are eight mahjor Japanese war criminals we hanged after WWII, including Hideki Tojo, and, Ibelieve, the General in charge during the Rape of Nanking. So worshipping at the shrine hardly constitutes cognizance of the actions of ther Japanese military during the war.