Shiso
Shisho, a common Vietnamese herb, could be sold for VND500-700 per leaf (2-3 cent) in Japan, used mostly by restaurants to wrap around food. In Vietnam, each leaf should cost about VND100-200 instead.
However, not all shiso leaves could be exported to foreign markets, as they must pass strict quality control tests to be eligible to be exported.
Jackfruit seed
Jackfruit seeds are often discarded in Vietnam, but this pedestrian delicacy has found its way onto Japan's kitchen tables. They could be sold for VND200,000 per kilogram ($9) in Japanese supermarkets.
Lime leaf
A Vietnamese herb that goes well with chicken, lime leaves are now exported to European markets at VND22,000-24,000 per kilogram ($1). In Vietnam, they might as well be free, as store owners often giveaway the leaves at zero cost as an add-on for other products.
Banana leaf
Banana leaves are commonly used in Vietnam to wrap around rice cakes or green rice, often at the cost of VND15,000-20,000 per kilogram (less than $1). However, they could fetch a very high price in Japan, sometimes for VND470,000 for a set of three ($20).
In order to be exported, banana leaves must pass several quality requirements, including a minimum width of 30 centimeters and a clean, smooth and homogeneous surface. They would then be disinfected and packed to be exported.
Dragonfruit
A sweet and sour tropical fruit, dragonfruits are often sold in Japan at VND180,000-200,000 per kilogram ($7-8). However, their prices in Vietnam could fall as low as VND2,000 per kilogram instead.
Currently, Vietnamese dragonfruits are exported to 40 foreign countries and territories.
Mango
This Vietnamese fruit is currently being exported to mainly South Korea, Japan and Singapore in high demands.
Mangos can be sold in Japan at $8-10 per kilogram. In Vietnam, prices could fall as low as VND7,000 per kilogram (31 cent).
Lychee
In Japanese supermarkets, lychees can be sold at VND400,000 for a set of 12 ($17). In Vietnam, they are often sold at VND40,000 per kilogram instead.