Requesting help to answer questions - about the Russian insp

[XiaoH]

Requesting help to answer questions - about the Russian inspection stamp on a postcard
The attached picture shows two postcards sent from Shanghai and Beijing to Europe during World War I, which were inspected and detained while passing through Russia.
My question is:
Firstly, where was the  "КОНФИСКОВАНО No.15" (Confiscated)  stamp numbered 15 stamped and used?
Secondly, where was the purple triangle inspection stamp  "Х. Ц." stamped and used in Russia? No similar stamp was found in the directory of relevant Russian inspection mails，and both of these handstamps  are not listed in the Speeckaert catalog or any other catalogs.
Looking forward to receiving answers from experts and postal friends
Thank you, everyone
Kind regards

Xiao Hong

[XiaoH]

the triangular handstamp "Х. Ц."