So what was the response from Japan.
Because it would be in everyone's interest that the two sides patch up their differences for the sake of the denuclearization process?

Well,... the only official response from the Japanese government was from Tokyo's Chief Cabinet Secretary Yoshihide Suga on Monday.
He said Japan welcomes the North's decision and sees the destruction of its nuclear test site as a move in the right direction.
But responding to a question on why Japanese reporters were not invited, Suga said Tokyo is not going to comment, adding it won't be swayed by the North and will maintain its stance as before.
But Japanese reporters seem to have reacted angrily.
A number of outlets reported that the demolition could be staged,... and the right-wing Sankei Shimbun newspaper even said the event is being used to earn the regime foreign currency.
Now while Japan does not play a big role in the North's denuclearization process, many experts say Pyongyang will need Japan's help if North Korea really wants to become a normal member of the international community.

"If all goes well, there will be the issue of settling a peace treaty on the Korean peninsula. And for North Korea, part of that is to normalize ties with long-time adversaries, including the U.S. and Japan. So, even for Pyongyang, it cannot totally exclude Japan from its diplomacy if it wants to be seen as a normal nation."

Japan also has considerable sway in international financial institutions, especially the Asian Development Bank.
Experts say once sanctions are lifted,... these banks will be open to invest in the North and help expand its market.
And as such,... to receive international backing, experts say Japan will have a big say and shouldn't be cast aside by the North.