Like other German civilians living abroad those in China were subject to call up in the regular German army as reservists as they would have been at home. Those in Tsingtao did their annual training with the III. Seebataillon.

During the Boxer Rebellion, German civilians formed an 800 strong "Kommando" Detachment to defend the city if needed. They did not see action.

When the First World War broke out German reservists living in China were called-up in the defence of Tsingtao. Many were already Tsingtao residents but other Germans travelled from Peking and all over China to answer the call, even non-combatant volunteers helped free up other fit men from administrative and other jobs. In all the reservists and volunteers added 76 officers and about 1,400 other ranks to the defence of Tsingtao. They formed two extra companies of the III. Seebataillon and manned artillery positions. These reservists wore regular Seebataillon and naval uniforms with no special distinctions.

In addition a Landsturm was formed of older and less fit Germans in the territory for internal police and guard duties.

Volunteers of the Kommando Detachment training in Tsingtao, 1900
They wear mixed items of naval, marine infantry and civilian dress.
Photo from BundesArchiv/WikiCommons

Reservists in the III. Seebatallion parade in Tsingtao
They wear the standard Marine Infantry uniform of a dark blue Litewka and peakless field cap with white hatband.
Photo from BundesArchiv/WikiCommons