Setsumatsusha is a fancy Japanese word that means "temporary shrine". Imagine you are a kid and your family just moved to a new house. Before you move in and get everything set up, you might stay in a temporary house or apartment. Setsumatsusha works the same way: it's a temporary place where people worship until the real shrine is built or fixed. In Japan, sometimes the actual shrine might be damaged or destroyed because of a natural disaster or other reasons, so people use a setsumatsusha until the actual shrine is fixed or rebuilt. It's like having a home away from home, but for worshipping instead of living.