JFE Steel has developed a high strength steel plate, “HBL385”, with lower limit yield strength of 385MPa, providing a combination of economic efficiency, earthquake resistance, and weldability. This developed steel has the middle strength between HBL355 and SA440, and good weldability equivalent to HBL355. Production of this steel plate was made possible for the first time by applying thermo-mechanical control process (TMCP) technology using the most advanced JFE Steel's on-line accelerated cooling system. Heat affected zone (HAZ) toughness of HBL385-E for high heat input welding was improved by applying JFE Steel's microstructural control technology for high heat input welding, “JFE EWEL,” accomplishing the Charpy absorbed energy value above 70J (average) at 0°C. The developed steel has been approved by Minister of Land, Infrastructure and Transport, and the actual application results of the developed steels are under increase.