Jankaku (雀カク) is a free Japanese media platform for checking and understanding mahjong through data. Its name combines the characters for “mahjong” and “確,” meaning certainty, reflecting its focus on reliable statistics rather than impressions. The site records every M.League match from the league’s 2018–19 inaugural season, with game data updated automatically the morning after match days.

Visitors can explore player and team statistics, rankings, luck indicators, matchup analysis, season records, and detailed match reports. Jankaku also offers learning articles covering mahjong rules, scoring, and strategy, alongside tools for calculating scores and waits and recording results. These resources are available without registration.

Beyond its data and educational content, the site features recommendations and listings for mahjong products, including automatic tables, tiles, mats, and books. Its coverage brings match analysis, practical learning resources, and product discovery together in one place for M.League followers and mahjong players. The platform also shares updates, rankings, and record alerts through its official social media account.