Recently we barbecued at Tokyo Metropolitan Nogawa Park (Chofu, Koganei, Mitaka)—a group harvest festival after renting rice paddies in Nagano for kids to farm; about thirty of all ages.
Under splendid autumn skies, adults brought camp gear, lit charcoal, and worked slowly over drinks while kids enjoyed athletics and ran on the lawn. Potluck ingredients (mostly core members—sorry). Grilled meat＝photo upper right and pricey Pacific saury this year＝photo lower right. Nearby, pork soup simmered and a Dutch oven stuffed pumpkin with mince, cooked slowly from above and below＝photo lower left—sweet pumpkin from a member's Tohoku family, delicious.
The BBQ area near the south main gate has plenty of shade—cool even in summer. Capacity 600; free with reservation (closes when full).
Nogawa Park's wide lawn and 8,450 trees—maple, zelkova, pine, cherry, cedar, camphor, oak—make you forget you are in the city. From Takebashi: Tozai Line → JR Chuo to Mitaka fastest 30 minutes, then 20 minutes by bus—or Seibu Tamagawa Line Tamagawa Station 50 minutes from Takebashi, 15 minutes' walk. Closer than you think.
Not just BBQ: the listed address (Mitaka Ohsawa) is the office; the park spans three cities (~400,000 m²), once ICU's golf course. Summer play by Nogawa River; cycling; kids' athletics; tennis (reservation); free wall tennis—satisfying for adults too. Tokyo Metropolitan Park Association lists more BBQ spots (http://www.tokyo-park.or.jp/special/bbq/#anc12).