透かし (すかし)watermark (in a stamp, banknote, etc.); openwork (engraving, carving, etc.)

透かし, its kanji, and other words that share them.Open this graph

Kanji in 透かし

不透明ふとうめいopaque; obscure
透明とうめいtransparent; clear
浸透しんとうpenetration (e.g. market); pervasion (e.g. thought, ideology)
透析とうせきdialysis
人工透析じんこうとうせき(artificial) dialysis
肩透かしかたすかしunder-shoulder swing-down; technique of grasping the arm of the opponent, the moment he comes forward, while stepping out of line and pushing down on the shoulder blade with the other hand, thus pulling him down
見透かすみすかすto see through; to see the true nature of something
透き通るすきとおるto be transparent; to be see-through

See how 透かし connects to the rest of Japanese.