Its ironic that I came across this information recently.
Back in college, My friend Tony (aka Anthony Tully), and I would discuss history and current world events. Well Tony, who is really into World War Two Japanese Navy history, and now has one book of his own under his belt (Battle of Surigao Strait); and a co-authorship on another one (Shattered Sword-The Untold Story of the Battle of Midway with Jonathan Parshall). Well, like I said before, we would talk about future military projections of power when we were going to Texas Tech University back in the early 1980s.
Back then, we still had to deal with the (in hindsight now) the tail end of the cold war. But our discussions would end up with Japan having to take on more responsibility for its defense against a more aggressive Red China of the future. The Japanese constitution forbids it to have Aircraft Carriers, a means of projecting power. That is one of the reasons why it is referred to as a Helicopter Destroyer.
So Japan would have to have Aircraft Carriers again is what we thought. Well, sure enough - that trend is taking place now. The Japanese Ministry of Defense released on Sept 7, 2009 its 4.85-trillion yen budget plan for the net fiscal year. The most notable items in that budget was an upgrade to the nation's missile defense system. The second item was the purchase of another helicopter carrier- correction, Helicopter Destroyer.
Based on the current Hyuga-calls helicopter destroyer class, the new helicopter carrier is expected to be 25% longer that the Hyugas and capable of carrying 9 helicopters that can conduct limited naval resupply as well as antisubmarine operations.
This is in light of the Chinese Navy's recent submarine construction. But, China is bulding its own flattops too now.
Currently, the 18,000-ton, 610 foot long, Hyuga (DDH 181) is jointed by sister ship Ise. A third ship of this class is still planned. The next carrier will be longer with a flight deck of 763 feet long. It will weigh in at about 25,000 tons. Currently these ships will operate the SH-60s of which 10 to 11 can be carried by the Hyuga class. Crew size is in the 350 personnel range.
Checking out Wikipedia, DDH-181(Hyuga) and sister DDH-182 (Ise), will be able to operate Harriers and F-35 Lightning IIs when they become operational. The ships will then be equipped with a 12 degree ski-jump.
As for weapons for self-protection; (16) Mk41 VLS (Vertical Launch System) cells for anti-aircraft and anti-ship missiles. (2)20mm Phalanx cannons. (2)triple 12.75-inch torpedo mounts.
Hyuga and Ise are of special interest to me. As a younger man, I was into building 1/700ths scale ship models from Tamiya and similar model companies. On of the first models I ever bought in this scale was of the Japanese WW2 hybrid battleship/carrier Ise. Both the Ise and the Hyuga were sunk in the same week(July 25) in World War 2.
Janes articles (http://www.janes.com/news/defence/naval/jni/jni090424_1_n.shtml)