The plan
Day 1: Shinkansen to Hiroshima, sightsee, watch a night game, stay overnight. Day 2: Morning sightseeing, return to Tokyo. Total cost: about ¥40,000-50,000 ($265-330) including trains, hotel, food, and ticket.
Day 1 schedule
Morning: Tokyo to Hiroshima
Take the 8:00 AM Nozomi Shinkansen from Tokyo Station. Arrive Hiroshima Station at 11:50 AM. Cost: ¥19,760 one-way (covered by JR Pass if you have one).
Afternoon: Sightseeing
12:00-14:00: Peace Memorial Park and Museum. 14:30-16:00: Hiroshima-style okonomiyaki lunch in Okonomimura. 16:30: Walk to MAZDA Stadium (10 minutes from Hiroshima Station).
Evening: Carp game
18:00: First pitch. Grab a Carp Udon and Hiroshima oysters inside the stadium. Game ends around 21:15.
After the game
Walk back to hotel near Hiroshima Station. Hotels in the ¥6,000-10,000 range are plentiful.
Day 2 options
Option A: Miyajima Island
Take the JR train to Miyajimaguchi (30 min), ferry to Miyajima (10 min). See the floating torii gate, feed the deer, eat momiji manju (maple leaf cake). Return to Hiroshima by 14:00, Shinkansen back to Tokyo by 18:00.
Option B: Direct return
Sleep in, grab breakfast okonomiyaki, take the late morning Shinkansen back to Tokyo.