PDBj, or the Protein Data Bank Japan, is a specialized database that provides access to three-dimensional structures of biological macromolecules, such as proteins and nucleic acids. It serves as a valuable resource for researchers in the fields of biochemistry, molecular biology, and structural biology, allowing them to study the intricate details of molecular structures. The database is part of the global Protein Data Bank network, which includes other regional databases like the RCSB PDB in the United States and PDBe in Europe. PDBj offers tools for visualization and analysis, facilitating scientific discoveries and advancements in understanding biological processes.