Tantōdori sakatemochi gokyō
Uke attacks with tanto yokomenuchi sakatemochi. "When Uke's arm is open, Nage can step in and bring the arm out. However, if Uke continues and changes the form of his arm by closing it, Nage can no longer lead the danger away."
So the initial attack is chudan tsuki sakatemochi - bang - and when Nage wants to lead Uke's arm Uke changes form.
"Nage must therefore immediately grab Uke's wrist with his second hand from below. Of course with chudan tsuki, that wasn't possible.
This allows Nage to lead Uke's arm to the ground. This is gokyo."