The computation of periods prescribed in this Act or in a Prefectural or Municipal Ordinance based on it is governed by Articles 139 through 141 and Article 143 of the Civil Code.
この法律又はこれに基づく条例に定める期間の計算については、民法第百三十九条から第百四十一条まで及び第百四十三条に定めるところによる。
Where a time limit determined by the provisions of this Act or a Prefectural or Municipal Ordinance based on it (excluding a time limit specified by Cabinet Order) falls on a holiday prescribed in Article 142 of the Civil Code or on any other day specified by Cabinet Order, the day following that day is deemed to be the time limit, notwithstanding the provisions of this Act or the Prefectural or Municipal Ordinance concerned.
この法律又はこれに基づく条例の規定により定められている期限（政令で定める期限を除く。）が民法第百四十二条に規定する休日その他政令で定める日に該当するときは、この法律又は当該条例の規定にかかわらず、これらの日の翌日をその期限とみなす。
Read this with the articles around it
Prefectural or Municipal Ordinance
条例
A rule a local government makes for itself: a prefecture (都道府県), a city, town or village (市町村), or one of Tokyo's special wards (特別区) (Local Autonomy Act, Articles 1-3, 281 and 283). Its assembly (議会), whose members the residents elect, passes it (Articles 89 and 96, paragraph (1), item (i)), and its head — the governor or the mayor (Article 139) — promulgates it, that is, makes it public so that it can take effect (Article 16). The Constitution lets local governments make them within the limits of Acts (Constitution, Article 94), and one may not go against the national laws and regulations (法令), such as Acts, Cabinet Orders (政令) and Ministerial Orders (省令) (Local Autonomy Act, Article 14, paragraph (1)). Unless national laws and regulations provide otherwise, a local government can impose a duty or restrict a right only by one of these (Article 14, paragraph (2)), and it may write into one penalties for breaking it, within limits the Local Autonomy Act sets (Article 14, paragraph (3)). It is made for that local government's own affairs (Article 2, paragraph (2) and Article 14, paragraph (1)), so the same matter can be handled differently from one place to the next. It is a local rule, not a national one: an "ordinance" in the name of a national rule, such as an Ordinance for Enforcement of an Act, is usually a Ministerial Order (省令) or another national instrument.
Written by AI using Constitution, Art. 94 and Local Autonomy Act, Arts. 1-3, 2, 14, 16, 89, 96, 139, 281, 283 as a reference.