Japan's Defense Ministry is weighing whether to share submarine technology developed by a contractor for the Maritime Self-Defense Force with the Royal Australian Navy, sources said.
Given that submarine technology is highly classified, doing so would signal strengthened cooperation among friendly nations in the Asia-Pacific region where the Chinese Navy has demonstrated a growing presence.
The sharing of military technology was made possible with the relaxation in 2011 of the three principles Japan had adhered to with regard to weapons exports. However, Japan has until now not shared such technology with any nation other than the United States.
According to high-ranking Defense Ministry officials, Australia sounded out Japan about getting submarine propulsion technology. Officials in Tokyo are now trying to determine what level of information to provide.
The request came on the heels of a visit in May 2012 to the MSDF Kure Base in Hiroshima Prefecture by a senior Australian official who inspected an advanced Soryu-class submarine.
Soryu-class submarines incorporate air-independent propulsion (AIP) technology. This allows a submarine to remain submerged for longer periods than those that have to surface to refresh their oxygen intake.
Japan, Germany and Sweden are among a small number of nations that operate submarines with AIP technology.
However, the contracts with foreign companies involved in the development of the technology carried restrictions on information disclosure. This means Defense Ministry officials must determine what level of technology can be shared with Australia without any comebacks.
The relaxation of the weapons export principles included a provision allowing joint development and production in instances where weapons exports had been approved.
While this seems clear-cut, an issue that still has to be addressed is the nature of technology being provided only one-way instead of mutual sharing.
According to Australia's 2009 defense white paper, Canberra intends to acquire 12 submarines to replace six outdated craft.
In response to queries by The Asahi Shimbun, an Australian Defense Department official said various alternatives were being considered.
Last April, Japan reached an agreement with Britain to begin joint development and production of military equipment.