  In this paper we describe the current status of the GRAPE-6 project to
develop a special-purpose computer with a peak speed exceeding 100 Tflops for
the simulation of astrophysical N-body problems. One of the main targets of the
GRAPE-6 project is the simulation of dense stellar systems. In this paper,
therefore, we overview the basic algorithms we use for the simulation of dense
stellar systems and their characteristics. We then describe how we designed
GRAPE hardwares to meet the requirements of these algorithms. GRAPE-6 will be
completed by the year 2001. As an example of what science can be done on
GRAPE-6, we describe our work on the galactic center with massive black holes
performed on GRAPE-4, the predecessor of GRAPE-6.
