While China last week allowed online bloggers to leak the first images of its prototype stealth jet fighter, Vietnam is revealing its own tricks in the transparency stakes - slipping photos of cutting-edge anti-aircraft missile batteries into a calendar.
The photo, accompanying the month of August in the Ministry of National Defence's 2011 calendar, is circulating among Hanoi-based diplomats and military analysts now eagerly watching Vietnam's build-up to counter China's military rise.
It appears to confirm that Vietnam has obtained crack Russian S300 PMU1 air defence systems, showing missile tubes mounted on a truck along with Vietnamese soldiers.
'We knew it was out there, but this is the first time it's been seen ... it is clearly in Vietnam and apparently operational,' one Hanoi-based envoy said. 'It is a subtle way of getting the message out: Vietnam's improving its defences.'
The PMU system has been compared favourably with the US Patriot missile that can target both enemy aircraft as well as a variety of missiles - and is capable of attacking multiple targets at a full range of heights.
Vietnam reportedly spent more than US$200 million to clinch the deal with Moscow, its former cold-war patron, two years ago. It has two batteries - a total of 12 launchers and more than 60 radar-guided missiles. China also fields the PMU.
The updated air defences appear to plug one of the more glaring holes in Vietnam's military modernisation. While it has brought state-of-the-art Russian planes and ships - and will soon have submarines - its once-feared air defences were widely thought to be falling into disrepair. Backed by then-Soviet technology, Hanoi shot down hundreds of US aircraft during the Vietnam war, including B-52 bombers and F-4 Phantoms, deploying telephone-pole sized missiles as well as fire from smaller arms.
Analysts believe both the leaking of the stealth photos and the publication of the calendar, filled with more routine pictures of military personnel on parade and regional defence ministers, serve as a timely reminder of the unusual nature of military transparency in a habitually secretive region. While both Vietnam and China have produced formal defence white papers in recent years, much key detail is missing. Leaking details more quietly serves to deliver messages to potential rivals and enemies without unduly angering neighbours.
'A country like Vietnam wants people to know what it has got and what it can do, but it doesn't want to be too provocative about it,' another envoy said. 'As secretive as it still is, at some point Hanoi has to let things slip to ensure its weapons can serve as a deterrent.'
Just as East Asia lacks any kind of formal security architecture to promote openness and transparency beyond the Association of Southeast Asian Nations, no register of sensitive weapons exists.