I·shi·ka·ri Bay (?sh??-kär??) An inlet of the Sea of Japan on the western coast of Hokkaido, Japan. The Ishikari River, about 445 km (275 mi) long, flows generally southwest from the mountainous interior of the island into the bay.American Heritage® Dictionary of the English Language, Fifth Edition. Copyright © 2016 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.