The Polish-Lithuanian armorial clan Kotwicz, bearing a coat of arms blasoned Argent, a fess Gules, produced several secondary offshoots, presumably as the result of heraldic augmentations: Kotwicz II (Argent, a pale Gules), and from the latter, Strzala (Gules, an arrow, barbed and flighted, point upward Argent), Siestrzeniec, and Siekierz (Gules, per fess embattled in three parts, the center conjoined in chief with a chevronel couped and debruissed of a barrulet Or, Argent). Altogether more than eighty different surnamed families are theoretically related in these clans by blood (and perhaps sometimes by adoption).

The Kotwicz clan is said to descend from several brothers of a family recorded variously as Buchheim, Puchheim, and Pöchner originally from Vörklabruck in Upper Austria, some of whose members moved first to Lusatia, and subsequently to Silesia, Poland, and Lithuania. The name Kotwicz is said to derive from a location in Lusatia where the Pöchner brothers built a castle, later known as Cottbus.

Siebmacher mentions a theory found in early armorials stating that Buchheim derives from the Scottish Buchan, as the family originates from members of the family of the Comyn Earls of Buchan who fled Scotland at the time of the destruction of that clan early in the 14th century.

The Kotwicz, Kotwicz II, and Siekierz arms may be seen illustrated at:

http://akromer.republika.pl/armorial_pocz.html

(The use of / in the spelling of surnames indicates a Polish-language accent on the preceding letter. This marking has been omitted in the case of the invariably acute-accented N in -enski/ -inski/-ynski suffixes.)