I had a chance to go exploring one of the many caves located on the south side of Nimitz Hill, formerly known as Fonte during the pre-war days. They are off the beaten path, but not hard to find if you know where to look for them. There are many caves in total, but most are small. These caves were used extensively by the Japanese during their defense of Guam following the American landings on July 21, 1944. The northern landing beach was directly below Fonte, and the Japanese had a commanding advantage being on the hilltop and were able to hold back the American advance in this sector for several days. These caves were key to there defense because they provided shelter from both naval bombardment and aerial attacks.
There is a cave located on the east side of Nimitz Hill, just along the road which is a National Park Service site. Originally, this site was said to be the command post of the Japanese army commander, General Takashina. In actuality, this cave was used as a communications station by the Japanese, and it is my belief that the caves, being on the exposed hilltop, would have been too exposed to be used as a HQ position. Any way, these caves were upgraded as fallout shelters in the post-war years for civil defense so they do not even look as they did during the war.
It is quite likely that one of the caves to the south of Nimitz Hill was used as the HQ of General Takashina. Even if they were not, they were absolutely used as shelters by Japanese troops. After five days of heavy fighting, the Marines had barely advanced up the sides of Fonte (Nimitz) Hill. Takashina believed that they were worn out and low on supplies. His plan, executed on the 5th night of the battle, was to amass six battalions (upwards of 5000 or more troops) to directly assault the Marine positions and hopefully push them back into the ocean. The attack was a frenzied one, but ultimately failed with many hundreds of attacking Japanese killed. This effectively turned the tide in the battle, and the Marines were able to capture the high ground the next day. Takashina himself was killed while trying to reposition his remaining troops in Northern Guam with plans to resist as long as possible from the jungle.