A high-density optically reconfigurable gate array (ORGA) is proposed to improve the gate density of conventional ORGAs, which are a type of Field Programmable Gate Array (FPGA). However, unlike FPGAs, an ORGA is reconfigured optically with external optical memories. A conventional ORGA has many programming elements, just as FPGAs do. One programming element consists of a photodiode to detect an optical reconfiguration signal; a latch, a flip-flop or a bit of memory to temporarily store the reconfiguration bit; and some transistors. Among those components, the latch, flip-flop, or memory occupies a large implementation area on a typical VLSI chip-, it prevents realization of a high-gate-density ORGA. This paper presents a high-density ORGA structure that eliminates latches, flip-flops, and memory using a dynamic method and a design of an ORGA-VLSI chip with four optically reconfigurable logic blocks, five optically reconfigurable switching matrices, and four optical reconfigurable I/O blocks including four I/O bits. It uses 0.35 mum 3-Metal CMOS process technology. This study also includes some experimental results.