Crucially the ICBM had a very long flight, with Japanese Chief Cabinet Secretary Hirokazu Matsuno indicating in a statement it flew for 74 minutes, which is being widely reported as the longest flight time recorded by any weapon launched by Pyongyang. 

Further statements from both Japanese and South Korean officials described a 620 mile flight of the projectile at a maximum altitude of 3,730 miles. It crashed into waters between the Korean peninsula and Japan. The North had tested its last ICBM in April.

The timing is also notable given that both South Korean President Yoon Suk Yeol and Japanese Prime Minister Fumio Kishida are currently attending the NATO summit in Vilnius, Lithuania. Yoon quickly summoned an emergency meeting of his national security council due to the launch.