* Bangladesh in process of buying 200,000 tonnes
* Japan may seek 250,000 tonnes from Vietnam-media
* Mekong Delta's paddy prices rise 4 percent
* Harvest of the biggest crop to end this month
By Ho Binh Minh
HANOI, April 5 (Reuters) - Demand for Vietnamese rice is strengthening, with deals totalling over 1 million tonnes sealed in recent weeks, while Japan may resume imports of the grain from the Southeast Asian country, state media and traders said.