Both countries are engaged in bitter, but separate territorial disputes with China.
The boat deal was announced in Hanoi during a visit by Japanese Foreign minister Fumio Kishida.
So far, there has been little reaction from Beijing.
Presenter: Sen Lam
Speaker: Professor Carl Thayer, Emeritus Professor at The University of New South Wales and Director of Thayer Consultancy
THAYER: To clarify first of all, these are both only to help the Vietnamese Coastguard in fishery surveillance. They are not combatant ships, but this is where the brunt of confrontation is occurring, it's China coastguard, the white-hulled ships, against their counterparts are not navy and so this is helping strengthening Vietnam's capacity in an area where it's very, very weak.
LAM: And also these are the weaker, reconditioned battles aren't they. How useful will they be in real terms?
THAYER: Well, let's say if Vietnam has about 30 ships in its fishery surveillance force, adding 6 more is 10 (as heard) per cent of the force, about 50 in the Coastguard. These are lightweight, they're 600 to 800 tonnes, China weighs in 2-thousand and that's been the problem with the ramming incidents. Two are fishery patrol boats and two are former commercial fishing craft. But they will be equipped with radar and that will help Vietnam in conducting surveillance and to protect its Exclusive Economic Zone.
LAM: So in some small measure, these ships will provide some form of deterrence against Vietnam's intentions to continue its oil search in the region?
THAYER: Well, the Coastguard is to protect Vietnam against intrusion to its Exclusive Economic Zone and the Fishery handles fisheries encroachment and maintains good law and order. The protection for offshore oil would first of all lie with the Coastguard and so far, Vietnam has been extremely reluctant to even deploy its military ships out there and I've discussed with foreign oil industry people in Vietnam recently. They are quite concerned about expanding their operations without the knowledge of the risk that they would take. But so far China, except for cable cutting incidents a few years ago, has left oil exploration activities by foreign partners in Vietnam alone. The oil rig was China's deliberate placement of a rig in Vietnamese waters, so it was as bilateral matter.
LAM: And, of course, the China placement of that rig, that was a source of much annoyance in mid July - are we seeing a calming of tempers now or not?
THAYER: Yes, China withdrew the rig a month early, claiming it had completed its operations, but also to protect the armada of ships that were protecting it from the typhoon that hit the area. So both sides have now withdrawn, so the water space is empty. Everybody is looking to next year, but between now and then, we're having the regional rounds of ASEAN-related meetings, the Regional Forum, so I suspect we're going to turn from confrontation to diplomatic exchanges and perhaps finally what Vietnam has been agitating for is for China to receive a high level visitor so they can try to repair some of the damage in the bilateral relations. It is at a very low level, but I think that the game now is less confrontation in the second half of this year and more diplomacy.
LAM: And Carl Thayer, Japan's gift, of course, is part of the Abe administration's decision to have the right to collective self-defence . How do you think this might sit with the Vietnamese psyche, if you like, given the fact that Japan's past war records are still remembered vividly in region, particularly in South East Asia?
THAYER: Well in 2006, they signed a strategic partnership agreement, which includes a defence clause. Prime Minister Abe was part of that. Then his first visit in his present office was to Vietnam and there's already a well established defence cooperation program between them based on a 2011 defence cooperation memorandum of understanding, none of this is relating to combat skills, the goodwill visits, training, IT cooperation, exchanges at all levels, and now, more recently and Australia has got involved supporting Vietnam in its first venture into United Nations peacekeeping.
LAM: So just very briefly. Japan's current gift or the latest gift to Vietnam might not raise temperatures between Japan and China?
THAYER: No, well, Japan has also given ships to the Philippines and the United States has promised some 20-million to Vietnam to aid its coastguard. So these small beer because of China's larger and much numerous ships, but are slowly building up capacity in an area that has been deficient in both countries.