High-T_c superconductors based on the new material design

We review the present status of the oxide superconductors from structural points of view. Tokura has recently introduced the new concept of a “block” and found the new material by new combinations of “blocks”. We propose here the new concept of “layer” by classifying the block. We discuss the possibility of the new block by reconstructuring the layer. We can design the new material by constructing the new blocks. Further perspectives on the new high-T_c superconductors of Cu and non-Cu materials are briefly discussed.