According to the latest ‘Cherry Blooming Forecast’, cherries in major spots (except for highlands) in Nagano Prefecture would begin blooming March 28th (Iida, Tenryu Gorge in Southern Nagano) till April 14th (Omachi, etc in Northern Nagano) and full-bloom around 4th to 19th.
At the popular spot, Matsumoto Castle, they might start blooming on April 3rd according to the forecast. An event ‘Nighttime Cherry Blossom Viewing’ will be held from three days after cherries begin blooming and continue 8 days (so possibly around April 6th till 13th)
The special illumination for the cherries will start from the same day and will continue two days longer (10 days).
On April 7th, maybe a little before full-blooming of cherries, ‘Sumo road-show’ will be held again in Matsumoto and on April 19th it will be held in Saku City. The last year’s road-shows in Matsumoto and Nagano City were heated because of a new hero ‘Mitake-umi’ from Kiso in Nagano Prefecture. You might see some sumo wrestlers viewing cherries somewhere in Matsumoto after the show if you are very lucky.
See here about the time, venue and ticket of the show in Matsumoto.