箱 is a Japanese kanji written with 15 strokes, listed here under the keyword “box”. It is built from 相 (inter-) and 竹 (bamboo). In Remembering the Kanji by James W. Heisig it is frame 1013.
On KumiJi Glyph Explorer, open the parts search and type “inter-” + “bamboo”. 箱 is among the results, together with every other character containing the same shapes.
Open 箱 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.