跨刀

to appear in sb's show / (fig.) to give one's support to an endeavor by taking on an important role in it

to step across / to stride over / to straddle / to span

knife / blade / single-edged sword / cutlass / CL:把[ba3] / (slang) dollar (loanword) / classifier for sets of one hundred sheets (of paper) / classifier for knife cuts or stabs