5 Kopek 1915 BC
10 Kopek 1916 BC
15 Kopek 1915 BC
20 Kopek 1915 BC
10 Kopek 1916 (Osaka)
Mintmasters:
BC = Viktor Smirnov (1913-1917)
Year 1914 was the last year with mintmarks on imperial Russian coins. After it, there were only mintmasters(BC=VS) initials under the eagle. There was no real need for mintmarks in Russia, since the only mint was in Petrograd (Untill 1914 called Sankt Peterburg). There was another series of silver coins without mintmark in Russia: some of the 10 and 15 kopeks of 1916 were made in Osaka, Japan with no mintmasters initials either.