What step of Initiating Abilities / Playing Cards does Mantis Tenkinja interrupt?
If you are tied on honor with your opponent, can you try to play Blackmail, interrupting with Tenkinja, so that you meet the play requirements of Blackmail?

You would check play restrictions (step 1) before you check cost restrictions (step 2) so therefore you could not play Blackmail if you were at the same honor total to your opponent. I recognize that this is a slight adjustment to how I ruled previously (when I said it triggered before step 1) but it is more correct to say that it triggers at step 2 of the Initiating Abilities/Playing Cards sequence, as step 2 is when costs are determined.

[Tyler Parrott, 18 September 2018]