Documents-Japanese WWII

[Marti]

My maternal grandfather was Martin Quince Porter 1912-1972. He was a school teacher with 4 daughters when he was drafted by the US Navy for WWII. Family legend states he was helping clear out offices and this made it into his pocket. He was afraid of what would happen to him if anyone found him with it. It was given to my mother when she accepted a job teaching American History. When I went to college (1991) I took it with me and had an international student from Japan translate the letter. I remember how shaken she was by it and asked how I got it. I was young and didn't realize how it could affect her. 
I'm uploading the document, her translation and a pic of Quince Porter. 
I'm very curious if anyone has seen something like this before?  It's one piece of paper with writing on front and back. I've shared different views of it.  I've also included the translation --I'm not even sure if it is correct. Any information or referral source would be greatly appreciated!

[DiGilio]

Although with my limited ability, this is a more accurate translation I believe.

 

The document is instructions, written by US forces, for Japanese garrisons on how to make contact with, and surrender to, allied forces following Japan's capitulation. There are no names, units, or signatures in the document, only generic titles (such as simply "commanding officer"). Its possible this may have been simply a draft of some sort. The only specific information is at the beginning, where it states it is aimed at the Japanese on Pagan Island (of the Marianas archipelago). This island was among those cut off and bypassed by allied forces during the advance towards Japan's home islands. It later came under US occupation.

 

Pagan Island garrison of the Japanese Military
Notice to the [Japanese] Commanding Officer
On 15 August, under the orders of the Emperor, the Empire of Japan has unconditionally surrendered to the Allied Powers. The military forces of Japan shall immediately discard their weapons and promptly surrender to Allied Forces. This unconditional surrender is an Imperial command that has come down from the Emperor of Japan. The officers and men of the Japanese armed forces on this island should respectfully comply with the emperor's will, ... [missing/incomplete text].
1 Your intention to consult with the allied forces will be recognized by placing two white crosses or two parachutes within a short distance of the airfield runway. 
2 When allied forces detect this signal, one allied warship will maneuver alongside the island and, through a Japanese person, convey the terms of surrender using a megaphone. This warship will raise a white flag on its mast.
3 When this warship arrives at the island, you shall do the following:
    (1) Using a large white flag, or illumination/smoke, indicate a suitable location for the landing of a small boat.
    (2) At this site, either the [Japanese] commanding officer or a representative of his shall greet the arrival of our boat and return to our warship to carry out discussions.
    (3?) [missing/incomplete text] ... will be immediately returned to the island under escort.
4 You shall immediately hand down orders to your subordinates on this island that it is forbidden to fire on any naval vessels or aircraft of the allied forces.

END
Commanding Officer, US Military
 

[Marti]

Oh my goodness!! Thank you so very much! I've always wondered about this document. You have answered many questions.

Marti

[sundance]

Marti, I find this very interesting. Do you know whose offices your grandfather was clearing out, American or Japanese? My dad was in the Pacific so I take a keen interest in all thing's Pacific theatre.

[1st Sgt CES]

Something that you never see and you know who it came home with