FUKUOKA, Japan — Graying but walking with ramrod-straight backs, Chinese men in their 70s and 80s quietly toured a coal-mining museum here recently. But in a moment of recognition reaching back to their youth, the sight of a shovel, a rake and a vise made them call out the Japanese names for the antiquated tools.

The words were seared in the memories of the men, who otherwise spoke no Japanese, when they were forced to toil in slavelike conditions in southern Japan’s mines during World War II.

Seventy-six laborers and relatives came to Japan from China in early November to pursue lawsuits against the Japanese government and companies, which refuse even to pay them their unpaid wartime wages, much less offer compensation.

“The Japanese government bears responsibility for our suffering, and so do companies,” said Tang Kunyuan, 80, who was worker “No. 66” at a mine here owned by Mitsubishi Mining, now known as Mitsubishi Materials, one of the world’s leading makers of metal and ceramic materials for the electronics industry.

“First, we want an apology, then compensation,” Mr. Tang said. “Mitsubishi Materials has done terrible things.”