Pocket Connection Hyperdimension

The protagonist accidentally discovered that his pocket was connected to a super dimension, so he began to explore how to use this ability... Generally speaking, it is like this, but, the slightly exciting content starts at least 100 chapters, the more exciting content is around 200 chapters, and the climax, which is the beginning of the real story, is around 500 chapters. I don't know if anyone can let me go further. You can read the work yourself for details. There is nothing to see in the early stage.