核 is a Japanese kanji written with 10 strokes, listed here under the keyword “nucleus”. It is built from 亥 (sign of the hog) and 木 (tree). In Remembering the Kanji by James W. Heisig it is frame 1638.
On KumiJi Glyph Explorer, open the parts search and type “sign of the hog” + “tree”. 核 is among the results, together with every other character containing the same shapes.
Open 核 in the interactive kanji search
to expand every part down to its smallest pieces, add your own names and mnemonic stories,
or search for other characters by their parts.