Japanese Nikkei and others reported that Toshiba and GE in talks to produce offshore WTG nacelle at Toshiba's Keihin Factory in Yokohama city, Kanagawa Pref..
NHK reported that they may reach a deal as early as March.

Toshiba has announced to step into offshore WTG equipment production business at "FY2020 Technology Strategy Briefing" held on 3 Dec. 2020.
And, Toshiba got some subsidy (for promoting domestic supply chain) from Japanese Ministry of Economy, Trade and Industry (METI) on 20 Nov. 2020 for refine their factory for nacelle production.

As Japan set ambitious offshore wind target (10GW by 2030 and 30GW to 45GW by 2040) and Japan content industry target (60% by 2040), to build nacelle factory in Japan is a very positive news for achieving above targets.

Reports:

Toshiba and GE in talks to produce offshore wind power equipment, on 22 Mar. 2021, by Asian Nikkei
https://asia.nikkei.com/Spotlight/Environment/Climate-Change/Toshiba-and-GE-in-talks-to-produce-offshore-wind-power-equipment

Toshiba eyes partnership with GE on wind power, on 23 Mar. 2021, by NHK World
https://www3.nhk.or.jp/nhkworld/en/news/20210223_02/

Toshiba in talks with GE to jointly produce wind power equipment, on 23 Mar. 2021, by Japan Times
https://www.japantimes.co.jp/news/2021/02/23/business/corporate-business/toshiba-ge-wind-power-equipment/

Reference:

FY2020 Technology Strategy Briefing, 0n 3 Dec. 2020, by Toshiba
https://www.toshiba.co.jp/about/ir/en/pr/pr20201203.htm
https://www.toshiba.co.jp/about/ir/en/pr/pdf/tpr20201203_1e.pdf
- page 12 : planning to produce cutting-edge wind turbines in Japan.

令和2年度「サプライチェーン対策のための国内投資促進事業費補助金」に係る補助事業者の採択結果について(in Japanese), on 20 Nov. 2020, by METI
https://www.meti.go.jp/information/publicoffer/saitaku/2020/s201120001.html
https://www.meti.go.jp/information/publicoffer/saitaku/2020/downloadfiles/s201120001.pdf
- No.34 東芝エネルギーシステムズ株式会社 7020001121200 発電用・送電用・配電用電気機械 器具製造業 風力発電設備部品 大企業 神奈川
(No.34 Toshiba, 7020001121200, for power production, power transmission, equipment production for large scale offshore wind turbine, big company. Kanagawa pref.)

The 2nd meeting of the Council for Government-Industry Dialogue for offshore wind, 0n 15 Dec. 2020, by JWPA
http://jwpa.jp/page_301_englishsite/jwpa/detail_e.html