Learn in the textbookCross-Tabulation and Advanced Visualization of Correlation
DefinitionA dual-axis chart (2軸グラフ) has a vertical axis with its own scale on each side, left and right, and overlays the series in one figure with each series tied to one of the two axes.
ExplanationFor example, the left axis may show amounts (in 100 million yen) and the right axis quantities (in thousands of units), with series of the same unit grouped on the same side. Because one axis can carry several series, first check the legend or the axis titles to see which axis each series belongs to.