This has the same reading as the kanji you learned, meaning you know the reading!
This word can also be read つるぎ, but in that case its meaning is limited to Western-style swords only. Because of the meaning difference, we only accept the けん reading (but you'll get another try if you enter つるぎ).
How much is this sword?
We decided to fight with swords at two in the morning.
I was interested in the subject, so I took careful notes during the lecture on the history of sabres.