Could be a much better movie .....

The fascinating story of the "Shindo Renmei" probably is difficult to be told in 90 or 120 minutes; I have no doubt, however, that a much better movie could be made, better screenplay, or at least an "understandable" story.
The main part of this story took place in west State of Sao Paulo – both north and southwest (Marilia, Tupa, Bastos, Andradina, etc). Of course, mention of the place and time would help understand the movie.
The movie begins and finish with teacher (Miyuki) writing a phrase - the same they wrote in homes were "traitors" live. Although not familiar with japanese "kanji" myself, to my knowledge what they wrote was something like "Betrayer of Fatherland" and not "Dirty Hearts". Probably at that time around 80% of the immigrants were turned to "kachigumi" (those who believed that Japan had won the war), but only a few of them became the "tokkotai" (the killers). Those who did not follow their belief were named "makegumi" (they understood that Japan really lost the war, signed surrender and their imperor agreed he was not a Son of the Gods)
Several points could be more clear in the movie: for instance the Shindo Renmei leaders make these "kachigumi" immigrants believe that imperial ships were coming to bring them back to Japan; several of them sold or lost all their belongings and came to Santos (port) waiting for those ships.
Even numbers displayed at the end are incorrect: casualties reported were: 23 imigrants were killed and around 150 wounded. In total around 30,000 members were arrested for investigation and 381 were judged and sentenced up to 30 years in prison.
In spite of the usual fact that is a typical fact Brazil forgets easily his story; in this case is part of the history of Japanese Immigration in Brazil – maybe a "war" that both sides do not want to remember. The role of Brazilian goverment (president Getulio Vargas supported the axis early in the WWII) maybe can be useful to understand that happened.
There are several documents of this period (available or retrievable) and a book - “Corações Sujos” by Fernando Morais.
For me this movie deserve a 5/10, just for us to remember this history. Nevertheless, I really would like to see this subject again, maybe as a TV mini-series.