In this week (15 to 21 April 2019), many scientific research institutions have "open house" events.
They are packed in the week because the week is designated as "Science and Technology Week" by the Japanese government. The web site of the "week" is (in Japanese) here http://stw.mext.go.jp/ (It seems that there is no page in English or other languages.)
In particular, many research institutions in the "Tsukuba Science City" have open house events in this week (in Japanese here http://stw.mext.go.jp/event/tsukuba.html ). I introduced institutions related to earth science in [my blog article on 17 Apr.] in Japanese.
I have a weekly lecture in English for short-term foreign students, and I think that the open house events are good opportunity for them. But, alas! I missed mentioning them in my lecture on Thursday (11 and 18 Apr.)
I was not able to prepare information of "how to get there" in time. It may be simple: "Take a train of Tsukuba Express, get off at Tsukuba station, and take a bus." But, what bus shall we get on? At what bus stop shall we get off? Some institutions have a good information page in English, but some do not. Once foreign students arrive at a research institution, they will probably find someone who can answer questions in English. But it is not sure whether people on the street can handle questions in other languages than in Japanese.
Anyway, I put here incomplete information as far as I have collected.
NARO (National Agriculture and Food Research Organization) http://www.naro.affrc.go.jp/english/
which includes NIAES (NARO Institute for Agro-Environmental Sciences) http://www.naro.affrc.go.jp/english/laboratory/niaes/index.html
Open house 19 Apr. (Fri.) (just in Japanese) http://www.naro.affrc.go.jp/event/list/2019/04/130330.html
(Information of some past open houses are shown in English http://www.naro.affrc.go.jp/english/outreach/open-day/index.html )
How to get to NARO headquarters map is here, but no information about buses. http://www.naro.affrc.go.jp/english/about-naro/naro-navi.html
Information about buses in Japanese is here. http://www.naro.affrc.go.jp/introduction/access.html
NIES (National Institute for Environmental Studies) http://www.nies.go.jp/index-e.html
Open house 20 Apr. (Sat.) (just in Japanese) https://www.nies.go.jp/event/kagaku/2019/
How to get to NIES https://www.nies.go.jp/gaiyo/kotu/index-e.html
Geological Survey of Japan (part of AIST) https://www.gsj.jp/en/index.html
Geological Museum, open regularly (closed on Monday and the day after a public holiday) https://www.gsj.jp/Muse/en/index.html
How to get to GSJ ... see the part of "AIST Tsukuba Central" https://www.aist.go.jp/aist_e/guidemap/tsukuba/tsukuba_map.html
NIED (National Research Institute for Earth Science and Disaster Resilience) http://www.bosai.go.jp/e/
Open house 21 Apr. (Sun.) (just in Japanese) http://www.bosai.go.jp/event/2019/openhouse/index.html
( The open house event last year was introduced in English as well http://www.bosai.go.jp/nied/2018_openhouse/ )
How to get to NIED http://www.bosai.go.jp/e/access/tsukuba.html
National Museum of Nature and Sciences http://www.kahaku.go.jp/english/ (Its main museum is in Ueno of Tokyo)
Tsukuba Research Departments http://www.kahaku.go.jp/english/institution/shinjyuku/index.html
Open house 21 Apr. (Sun.) (just in Japanese) http://www.kahaku.go.jp/event/2019/04open_labo/
Tsukuba Botanical Garden open regularly (closed on Monday and the day after a public holiday) http://www.tbg.kahaku.go.jp/english/index.php http://www.tbg.kahaku.go.jp/english/userguide/guide/index.html
Geospatial Information Authority of Japan (GSI, formerly Geographical Survey Institute) http://www.gsi.go.jp/ENGLISH/index.html
The Science Museum of Map and Survey open regularly (closed on Monday and the day after a public holiday) http://www.gsi.go.jp/ENGLISH/page_e30226.html http://www.gsi.go.jp/ENGLISH/page_e30227.html
There are special events during the "Science Week" there.
How to get to GSI http://www.gsi.go.jp/ENGLISH/page_e30007.html
Meteorological Research Institute http://www.mri-jma.go.jp/index_en.html
Open house, 17 Apr. (Wed.) (just in Japanese) http://www.mri-jma.go.jp/Topics/H31/310417/ippankoukai2019.html
How to get to MRI http://www.mri-jma.go.jp/Information/map_n.html