Welfred,
I have a number of things to say about your rocks, but I don?t know if there is room or time to tell it all.
A. Your compass direction of 5 degrees off north is probably meaningless, since magnetic north has changed a number of times and locations since 1945. With a little research you could find out where magnetic north was during that year and see if it really points to something that stands out. I would imagine your line is at that location.
B. You need to find out what kind of measuring system the Japanese used in 1942. They were probably metric and not feet, but I don?t have a clue.
C. If it?s true the guerrilla's could have been responsible for the bullets, then the local priest was probably trained by a Spaniard or someone of Spanish extraction. If so, the guerrilla's could have been hiding supplies or a treasure, since they were attacking the Japanese.
D. Historically speaking the symbols I see are not of Japanese origin, but possibly of Spanish origin. If you look at the bottom picture at the bottom of the rock you see the broken edge that looks like an inverted V pointing at an approximate 35 degree angle. It is pointing at something in this direction. Whatever it is will probably be within eyesight if you knock down all the foliage, if there is any.
E. For future reference, and for all you other sign and symbol hunters, you might carry some artist charcoal sticks in your backpack. When you find rocks like this, mark what ever looks like a sign and take a picture of it. This is better than white chalk like I see a number of picture have, and gives better definitions. The next time it rains the chalk will wash off.
I?ll stop at this point, in case there are others who want to discuss the probability I?m wrong. Some of you are on the right track with some of the symbols you see. If you want to hear the rest of my thoughts I will continue later.