N.H. Rev. Stat. § 490:4
The supreme court shall have general superintendence of all courts of inferior jurisdiction to prevent and correct errors and abuses, including the authority to approve rules of court and prescribe and administer canons of ethics with respect to such courts, shall have exclusive authority to issue writs of error, and may issue writs of certiorari, prohibition, habeas corpus, and all other writs and processes to other courts, to corporations and to individuals, and shall do and perform all the duties reasonably requisite and necessary to be done by a court of final jurisdiction of questions of law and general superintendence of inferior courts.
RSA 490:4
RS 171:2, 3. CS 181:5, 6. 1855, 1659:1, 10. 1859, 2211:3. GS 189:1. GL 208:1. 1885, 42:1. PS 204:2. 1901, 78:7. PL 315 :2. RL 369:2. RSA 490:4. 1971, 341:1, eff. Aug. 24, 1971.