The K computer has approximately 670,000 processor cores (the smallest processing units in the computer). High-performance computation and processing of a huge amount of data can best be realized by work sharing and coordinated parallel computation using these cores. Development of programs suitable for parallel distributed processing then is the key to achieving full use of the computational power of the K computer. Therefore, we have developed a programming language with which any programmer can easily write parallel programs. And because balanced parallel computation with a uniform distribution of workload among the cores is essential to make full use of the K computer’s resources, we are also developing a performance analysis tool that helps programmers to understand at a glance the status and workload of all the cores. By using this tool, programmers will be able to identify which part of a program needs improving.