An extremely thick weight is also achieved in TP Sky Modern by widening the inside space between strokes. In the Extra bold weight, Blk (Black) strokes have been repeatedly adjusted, so kanji, kana, and Latin, with differences in the number of strokes can be seen in order even when they are placed side by side. This manages both thickness and visibility by strengthening the contrast between straight lines and curved lines, making strokes longer to allow a generous structure. UL (Ultra Light) and EL (Extra Light) are weights with the strength in narrowness, lightness, and transparency; due to the line width set almost the same, a sense of uniformity is generated. As the line width from L (Light) to H (Heavy) is designed to be visually seen as uniform, it achieves a stable black wash in typesetting.

https://typeproject.com/en/fonts/tpskymodern