High Performance Heterogeneous Coupling Computing with WaitIO This talk presents a high performance communication library to couple multiple MPI programs for heterogeneous coupling computing called h3-Open-SYS/WaitIO (WaitIO for short). WaitIO provides an inter-program communication environment among MPI programs and supports different MPI libraries with various interconnects and processor types. This talk shows the basics of WaitIO and the application examples with JSC collaboration and related projects including the JHPC-quantum project. This talk also compares the performance between InfiniBand and Tofu-D interconnect.