包丁 and 刃: a whole knife and its blade
Distinguish a kitchen knife from its cutting edge, reading instrumental で and part-linking の.
The whole kitchen knife
包丁, read ほうちょう, means kitchen knife. 包丁で野菜を切りました。 says that someone cut vegetables with a kitchen knife.
包丁を引き出しにしまいました。 means putting the knife away in a drawer. Distinguish the tool role marked by で from the stored object marked by を.
The cutting part
刃, read は, means blade or cutting edge. 包丁の刃が欠けています。 says that the knife's edge is chipped.
刃を研ぎました。 means sharpening the blade. Do not replace that part with the handle.
Whole and part
包丁の柄を交換しました。 means replacing the knife's handle. 柄 and 刃 refer to different parts of the same tool.
新しい包丁ですが、刃はまだ使っていません。 says that it is a new kitchen knife, but its blade has not been used yet. Separate the item owned from its usage history.
What is damaged in 包丁の刃が欠けています?
Show the answer and why
The knife's cutting edge. Distinguish the name of the whole tool from the name of its part.