n. (Hira=ほこ) halberd, old fashioned weapon with both a spear and a battle-ax; arms, weapons, firearms

n. (Trad=矛, Pinyin=mao2) spear, lance, pike

n. (Simp=矛, Pinyin=mao2) spear, lance, pike

wang2 ji3 de2 mao2
Losing a halberd and gaining a spear
The loss is made up by the gain.

zi4 xiang1 mao2 dun4
Using one's own spear to strike one's own shield.
Referring to a person who argues or acts in such a way that he cannot justify himself. Painting oneself into a corner with bad arguments. Contradicting oneself. Compare with 出尔反尔 (chu1 er3 fan3 er3).