The lake contains a big island, which is not visible in the regular OSM (only that there is a forest when you zoom in). In the editor it is visible, that obviously the island was done by its outlines, but not treated in the right way or with the right attributes. In my opninion it needs an experienced mapper to solve this problem. Furthermore, on the island are lots of trails, panoramic views, picnic sites etc. which need to be shown. The person, who will go there to do it, will be rewarded by a stunning landscape ;-)
One more thing: on the lake is a boat line connecting the island with the town but also some other points around the island.

京ヶ瀬中学校のグラウンド (OSM data version: 2017-01-19T15:17:02Z) #mapsme

北西からの尾根道は、このまま南下しており、北に折り返す道は存在しない。

Hayama Marina

#Mapy.cz user reports: "here is the trail - stairs"

The place has gone or never existed. This is an auto-generated note from MAPS.ME application: a user reports a POI that is visible on a map (which can be outdated), but cannot be found on the ground.
POI name: Akihabara
POI types: tourism-attraction
OSM data version: 2019-04-19T10:36:02Z
#mapsme

"サンクスからファミリーマートに変更"
POI name: サンクス
POI types: wheelchair-yes shop-convenience internet_access-wlan
OSM data version: 2019-03-28T14:13:02Z
#mapsme

築地-地鐵站 (OSM data version: 2016-03-14T15:50:02Z) #mapsme

aha, kaip ir veikia

そこ