The Samurai's Honor Event started today, August 12. The event has 15 days to run and 17 stages to complete. This means it is impossible to complete the event and obtain the type 74 tank.
This must be an error. In prior events AW has always given us a few more days than needed to complete the event. Why would they bother with an event that is impossible to complete?
On second thought; as it turns out, the event runs until August 28. This should give us enough time to complete the stages. The only error appears to be in the game where the counter, on the event screen, indicates only 15 days remaining on a 17 stage event.