竜りゅうの歯は

expression, noun

dragon's teeth

Military term for anti-tank obstacles resembling a row of pointed teeth. Also used in mythological contexts.

• 戦せん車しゃの侵しん入にゅうを防ふせぐため、国こっ境きょうに竜りゅうの歯はが設せっ置ちされた。

  Dragon's teeth were installed at the border to prevent tank incursions.

• 神しん話わでは、竜りゅうの歯はをまくと戦せん士しが生うまれると言いわれる。

  In mythology, it is said that sowing dragon's teeth gives birth to warriors.