TOKYO—The northern Japanese city of Sapporo is set to announce what it says will be a reduction in costs that will make it an attractive venue for the 2030 Winter Olympics. City officials were expect to announce details on Monday. The announcement comes almost four months after the delayed Tokyo Olympics closed with officials costs estimated at $15.4 billion. Some estimates suggest the costs might have been twice that much, and all but about $6 billion was public money. Organizers have not yet announced final budget figures for the Tokyo Games. Sapporo, which held the 1972 Winter Olympics, is considered a leading candidate. It helped solidify its case by stepping in and serving as the venue for race walks and marathons for the Tokyo Olympics. The International Olympic Committee moved these events on short notice to Sapporo in 2019, fearing Tokyo’s hot summer weather. Other areas that have expressed interest …