For a description of the weapons used and of the manner of using them, the reader is referred to Chapter XI.
In the description of the Manóbo house (Chapter V), reference was made to the high houses erected for defense when an unusual attack is expected. Tree houses, at the time I left the valley, were very few and far between, even in the eastern Cordillera and at the headwaters of the Tágo River.
Besides building high houses and resorting to devices referred to in Chapter V, the Manóbos occasionally slash down the surrounding forest in such a way as to form a veritable abatis of timber.
In one place I saw a very unique and effective form of defense. A fence surrounded the house. To gain access to the latter it was necessary to ascend a notched pole about 2 meters high and then to pass along two horizontal bamboo poles about 10 meters long. Numerous deadly bamboo caltrops bristled out of the ground underneath the precarious bamboo bridge that led to a platform whence the house could be reached only by climbing the usual notched pole. Whosoever ventured to cross this perilous bridge, would certainly meet death from one source or another, either from the hurtling shower of arrows from above or from the bristling caltrops below.
THE ORIGIN OF WAR
Fighting arises from one or more of the following causes: Vendettas, sexual infringements, debts, and sometimes from a system of private seizure, by which the property or life of an innocent third party is taken. The Manóbo expresses the same thing in a simpler way by saying that war has its origin in two things, namely "debt (blood debt included) and deceit." It has been said that glory and the capture of slaves are the springs of war in Manóboland, but this, in my opinion, is not true. Nor will I concede that war is undertaken for merely religious reasons. It is my belief, verified by numerous observations made during several years of intimate dealing with Manóbos throughout eastern Mindanáo, that fighting or killing takes place in order to redress a wrong or to collect a debt, whether it be of blood or of anything else. It is true that many who have no grievance, take part merely for the sport, the spoil, and the glory of it, but in no case that I know of was there wanting on the part of those who inaugurated the war a real and reasonable motive. I have heard of cases of unjust warfare but my informants were enemies of the parties against whom they complained and most probably were calumniating them.
VENDETTAS
Vendettas, which exist in many more enlightened countries of the world, are the most common cause of war, or it would be better to say, of the continuance of war.