anu ary ▁ 1 9 3 7 ); ▁then ▁the ▁trial ▁of ▁Red ▁Army ▁gener als , ▁including ▁Marsh al ▁T uk h ache v sky ▁( J une ▁ 1 9 3 7 ); ▁and ▁finally ▁the ▁Tri al ▁of ▁the ▁Tw enty ▁One ▁( including ▁B uk har in ) ▁in ▁March ▁ 1 9 3 8 . ▁During ▁these , ▁the ▁defend ants ▁typically ▁conf essed ▁to ▁sab ot age , ▁sp ying , ▁counter - re volution , ▁and ▁consp iring ▁with ▁Germany ▁and ▁Japan ▁to ▁in va de ▁and ▁partition ▁the ▁Soviet ▁Union . ▁The ▁initial ▁tri als ▁in ▁ 1 9 3 5 – 3 6 ▁were ▁carried ▁out ▁by ▁the ▁O G PU ▁under ▁Gen rik h ▁Y ag oda . ▁In ▁turn ▁the ▁pro sec utors ▁were ▁tried ▁and ▁executed . ▁The ▁secret ▁police ▁were ▁renamed ▁the ▁NK VD ▁and ▁control ▁given ▁to ▁Nikol ai ▁Y ez hov , ▁known ▁as ▁the ▁" B lo ody ▁D war f ". ▁ ▁The ▁" Gre at ▁Pur ge " ▁swe pt ▁the ▁Soviet ▁Union ▁in ▁ 1 9 3 7 . ▁It ▁was ▁widely ▁known ▁as ▁the ▁" Y ez hov sch ina ", ▁the ▁" Re ign ▁of ▁Y ez hov ". ▁The ▁rate ▁of ▁arr ests ▁was ▁st agger ing . ▁In ▁the ▁armed ▁forces ▁alone , ▁ 3 4 , 0 0 0 ▁officers ▁were ▁p urg ed ▁including ▁many ▁at ▁the ▁higher ▁ranks . ▁▁ ▁The ▁entire ▁Polit b uro ▁and ▁most