I think the attached newspaper article is what you're alluding to? Do you have any concrete information about Japan's submarines just being kept for 20 years and then scrapped? Or any Japanese plans to give them to the Philippines for free? Even the US charges an minimal amount for the Hamilton's transfer to the Philippines?Japan and Philippines just signed some sort of military agreement and some articles are saying that help from Japan would be to help the Phils improve it's maritime in particular.
This and Japan's recent lifting of their ban on military exports last Dec. 2011 should pave the way for them to give Philippines some needed 2nd-hand submarines.
Japan mostly only keep their subs not more than 20 years and then they just scrap it. Most countries keep their subs at least for 30 years. Just sell some of those to Phils. plus 1-2 trainer subs as well.
Philippines, Japan to enhance maritime security ties - Yahoo! News Philippines