In 2001, an archaeological field work was done by the Archaeological Studies Program of the University of the Philippines with the National Museum (NatMuse) at Arubo, Nueva Ecija. The investigation of the site came from the recommendation of NatMuse in 1996 when the grandson of the owner of the land lend the NatMuse two stone tools with some fossilized wood for examination . There were 200 finds collected, 18 of which were characterized.
Fast forward to 2010.
E.Z. Dizon and A.F. Pawlik writing in Quarternary International , said the find maybe important in that: 1) this maybe the oldest in the Philippines, pre-Tabonian; 2) it has similarities with the Javan Lower Palaeolithic Pajitanian industry and the Lower Palaeolithic sites in South China but not with the Tabon and Calloa finds; and 3) it challenges the suggestion that the dominant lithic technologies in the Philippines is expedient strategies (smash and grab).
What are these finds?
The picture on the left is a bifacial handaxe discovered in 1996 while the picture at the bottom shows some of the tools they saw. The authors say, “Arubo has a distinctive assemblage, significantly different from the stereotyped ‘‘chopper/chopping tool industries’’…. it has a fully bifacial component.”
“There is also evidence for curation and re-use in microscopic use-wear analyses as well as a variation in core preparation and core reduction.”
They add that the morphology of the artefacts would fit into the Lower Palaeolithic, and the handaxe is even of Acheulean-type.
The authors compared the recorded sequences for the Palaeolithic in the Philippines from Tabon Cave (an Upper Palaeolithic stratigraphy, ~50 000 BP), and from Callao Cave (~30 000 BP). The artefacts they said differs from the Callao and Tabon caves. They also said, “the Tabonian and the Calloa industries are small-sized flake assemblages with few retouched tools that continued into the Holocene.”
“The absence of any signs of a Neolithic or more recent occupation at Arubo, neither potsherds nor ground tools, were found during the extensive surveys, are at least hints for a terminus ante quem and a pre-Tabonian age of the Arubo artefacts.” 
The authors write that although there is little/no similarities with the Tabon and Calloa finds, there are similar forms in the Javan Lower Palaeolithic Pajitanian industry (such as the horse-hoof core) and the Lower Palaeolithic sites in South China where handaxes and other bifacial and unifacial forms similar to Arubo are frequently observed.
The authors say, “If the Arubo assemblage would have been located somewhere in Africa or Eurasia, a relative chronological classification into the Lower Palaeolithic based on Typology certainly could be established without much dispute.”
So, who are these people from the Arubo find? How did they get there?
 A. F. Pawlik, “The Palaeolithic Site of Arubo 1 in Central Luzon, Philippines”, Indo-Pacific Prehistory Association Bulletin, 24 (2004). click here for the article.
 E. Z. Dizon and A. F. Pawlik, “The lower Palaeolithic record in the Philippines”, Quaternary International 223-224 (2010). doi:10.1016/j.quaint.2009.10.002.