Everyone knows why Jesus died. Christians say he died for our sins. But why did Oyasama have to die 25 years before her time? Yes, most Tenrikyo people believe that she died so she could go out to help us spread the truth to the world. In translating the Osashizu, it is God that steps out and goes out to the world to save others. It is not Oyasama.
But again why did Oyasama have to die? In the Osashizu, when Oyasama was ill, God asked the followers if they wanted to open the portal to God, to spread the teachings to the world. What does this mean? Please be patient and let me try to explain. Oyasama was the shrine of God. People had to pray through her to get to God. I guess it is like the Catholic Church, where people have to talk to a priest to communicate to God. I imagine how hard it was for people to get to Oyasama to pray, especially when people were afraid of the authorities, and when she was inaccessible in confinement. So there were a limited amount of people that had access to God, and a more limited amount of people who had a sincere mind having access to God. When you understand this, you will understand the definition of kara and nihon that are mentioned in the Ofudesaki. Niihon are the people who have a sincere mind and have access to God. So in the early days of the teachings, Nihon was very small. Kara are people that do not have access to God. This is most of the world. In the Ofudesaki, God tells us that kara will become nihon.
When Oyasama passed away, it is my belief that her soul returned to the Origin, or the site where the Kanrodai will be erected when everyone is purified. This is the Ojiba or point of location where God descended from heaven. This now becomes the focal point where our prayers are directed toward, where Oyasama and God are present. So now the world has access or a portal to God, instead of a few people. Unknown to the early followers, they were asking God to terminate the physical presence of Oyasama, so the teachings could be spread to the world. The portal or access to God has been opened to the world now. Having this information, how do we spread our truth to the world? The answers are clearly in the Ofudesaki!