四十八刻制。一日十二辰刻，一辰刻が四刻（一刻開始），一刻が十分（零分開始），一分が現在の3分。子三刻が現在の午後12時。

平安時代の延長5年（927年）に藤原時平ら（時平死後は藤原忠平）により編纂された『延喜式』（律令の施行細則）に付随する時刻制度。読みは「えんぎしき」。

五十刻制。一日十二辰刻，一辰刻が四刻一分（初刻開始），一刻が六分（初刻は五と二分の一分，四刻は一と二分の一分），一分が現在の4分48秒。子二刻一分が現在の午後12時（午前0時）。

奈良時代から明治5年（1872年）の改暦まで使用された具注暦（漢文の暦本）に付随する時刻制度。本アプリは藤原道長の『御堂関白記』で用いられた時刻制度を四捨六入説で解釈して採用している。読みは「ぐちゅうれき」。

百刻制。一日十二辰刻，一辰刻が八刻と二十八分（初刻，零分開始），一刻が八十四分で現在の14分24秒，一分が現在の約10.29秒。子四刻十三分が現在の午後12時（午前0時）。

平安時代の貞観4年（862年）から江戸時代の貞享元年（1684年）までの823年間使用された宣明暦（太陰太陽暦の暦法）に付随する時刻制度。とくに源経頼の『左経記』（1027年の月蝕，1028年の日蝕記録）および中山忠親の『山槐記』（1155年の月蝕記録）以降で使用された。読みは「せんみょうれき」。

四十八刻制。一日十二辰刻，一辰刻が四刻（一刻開始），一刻が十分（一分開始），一分が現在の3分。子三刻一分が現在の午後12時（午前0時）。

延喜式に準ずる時刻制度。とくに藤原実資の『小右記』（1029年の日蝕記録）後，藤原宗忠の『中右記』（1097年の月蝕記録）に至るまでの間に使用された。

百刻制。一日十二辰刻，一辰刻が八刻と三分の一（初刻開始），一刻が現在の14分24秒で八刻のみ現在の4分48秒。子四刻が現在の午後12時（午前0時）。

鎌倉時代から明治5年（1872年）の改暦まで使用された仮名暦（仮名文の和暦）に示された時刻制度。江戸時代には貞享暦（貞享2年，1685年），宝暦暦（宝暦5年，1755年），寛政暦（寛政10年，1798年）で使用された。読みは「かなごよみ」。

百刻制。一日十二辰刻，一辰刻は八刻三分の一で一辰刻を二等分した前半を初刻，後半を正刻と呼ぶ。それぞれ四刻と六分の一の長さ（初刻開始）。一刻が現在の14分24秒で四刻のみ現在の2分24秒。子正初刻が現在の午後12時（午前0時）。

平安時代にはすでに使用されていたとされる七曜暦（天体暦）に付随する時刻制度で，鎌倉時代に中絶。渋川春海により江戸時代の貞享2年（1685年）に再開され，明治5年（1872年）の改暦まで使用された。読みは「しちようれき」。

夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻は十分（零分開始），一分が現在の約12分。夜明けが明六つ時，日暮れが暮六つ時。暁九つ時あたりが現在の午後12時（午前0時）。

江戸時代の天保暦（天保15年，1844年）に付随する時刻制度。読みは「てんぽうれき」。

昼（夜明けから日暮れ）は天保暦と同じで六辰刻に等分。一辰刻は十分（零分開始），一分が現在の約12分。夜（日暮れから夜明け）は昼とは別の単位を用い，夜の時間を五等分したものを更（一更開始）と呼んだ。一更が五点（一点開始）。一点が現在の約28分48秒。夜明けが明六つ時，日暮れが一更一点。三更三点あたりが現在の午後12時（午前0時）。

夜の時刻を示すため時刻制度で奈良朝以降に使用されたが，本アプリが表示する時刻は江戸時代に使用された方法による。読みは「こうてんじこくほう」。

夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻が二尺に相当。一寸が現在の約6分，一分が現在の約36秒。夜明けが明六つ時，日暮れが暮六つ時。暁九つ時あたりが現在の午後12時（午前0時）。

江戸時代に尺時計が普及するにつれ広まった時刻法。

不定時法。夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻が一尺に相当。一寸が現在の約12分，一分が現在の約72秒。半時ごとの時刻を基準に二寸五分で経過時間（廻）と残り時間（前）の表記が変わる。夜明けが明六つ時，日暮れが暮六つ時。暁九つ時あたりが現在の午後12時（午前0時）。

江戸時代に尺時計が普及するにつれ広まった時刻法。

夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻を三等分し，それぞれ上刻，中刻，下刻とした。一刻が現在の約40分。夜明けが卯之中刻，日暮れが酉之中刻。子之中刻あたりが現在の午後12時（午前0時）。

江戸時代に使用された時刻制度で，上・中・下刻の本来の区分法であるが，民間には普及しなかった。大野広城の『青標紙』（天保11年，1840年）に記載されている区分。

不定時法。夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻を二等分し，前半を上刻，後半を中刻とし，次の辰刻の前半を下刻とした。一刻が現在の約60分。夜明けが卯之中刻，日暮れが酉之中刻。子之中刻あたりが現在の午後12時（午前0時）。

江戸時代に民間で普及した時刻制度で江戸幕府執政方（老中）の区分。

夜明けと日暮れ（または日暮れと夜明け）の時間を六辰刻に等分。一辰刻を二等分し，前半を（前の辰刻の）下刻，後半を上刻，次の辰刻の前半を中刻とした。一刻が現在の約60分。夜明けが卯之上刻，日暮れが酉之上刻。子之上刻あたりが現在の午後12時（午前0時）。

江戸時代に民間で普及した時刻制度だが，時の鐘の時刻が辰刻の開始と一部で認識されていたため半時（現在の約1時間）の差がある。地方（京・大坂ほか）在勤方の区分。

It was used in the Engishiki, which is a compilation of detailed regulations for the enforcement of the Ritsuryo (Japan's historical law system). It was compiled in 927 during the Heian era

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is divided into 4 koku (刻). Each koku consists of 10 bu (分), with 1 bu equivalent to 3 minutes in the present day. Midnight (12 a.m.) is referred to as “Ne no san-koku” (子三刻).

It was used in the Guchureki, which is a calendar written in classical Chinese. This system was used from the Nara era to the early Meiji era (c. 710–1872).

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is 4 koku (刻) (start is 0 koku) and 1 bu (分). 1 koku is basically 6 bu, but 0 koku is 5.5 bu, and 4 koku is 1.5 bu. 1 bu is 4 minutes and 48 seconds in the present day. Midnight (12 a.m.) is referred to as “Ne no ni-koku ichi-bu” (子二刻一分).

It was used in the Semmyoreki, which is a lunisolar calendar. This system was used from the Heian era to the Edo era (862–1684).

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is 8 koku (刻) and 28 bu (分). 1 koku is 84 bu. 1 bu is about 10.29 seconds in the present day. Midnight (12 a.m.) is referred to as “Ne no shi-koku ju-san-bu” (子四刻十三分).

It is similar to the one used in the Engishiki (927). This system was used approximately from 1029 to 1097.

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is divided into 4 koku (刻). Each koku consists of 10 bu (分), with 1 bu equivalent to 3 minutes in the present day. Midnight (12 a.m.) is referred to as “Ne no san-koku ichi-bu” (子三刻一分).

It was used in the Kanagoyomi, which is a Japanese calendar written in kana. This system was used from the Kamakura era to the early Meiji era (c. 1185–1872).

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is 8 koku (刻) and one third. 1 koku is 14 minutes and 24 seconds in the present day. Midnight (12 a.m.) is referred to as “Ne no shi-koku” (子四刻).

It was used in the Shichiyoreki, which is an ephemeris. This system was used from previous the Heian era to the early Meiji era (c. 794–1872).

In this system, 1 shin-koku (辰刻) represents one-twelfth of a day and is 8 koku (刻) and one third. The first half of shin-koku is called sho (初), and the second half is called sei (正). 1 koku is 14 minutes and 24 seconds in the present day. Midnight (12 a.m.) is referred to as “Ne no sei sho-koku” (子正初刻).

It was used in the Temporeki, which is the last Japanese calendar. This system was used in the late Edo era (1844–1872).

In this system, 1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to next dawn) and is 10 bu (分). 1 bu is about 12 minutes in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Akatsuki kokonotsu-doki” (暁九つ時).

Historically, it was used from the Nara era (c. 710–), but this app uses a system that was prevalent during the Edo era (until 1872).

During daytime, it operates the same as the Temporeki. However, during nighttime, 1 ko (更) represents one-fifth of the time from dusk to dawn and is divided into 5 ten (点). Each ten is approximately 28 minutes and 48 seconds in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “San-ko san-ten” (三更三点).

It was used in the Edo era. It became popular alongside the spread of Shaku-Dokei, an old Japanese clock.

In this system, 1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to the next dawn). 1 shin-koku is equivalent to 2 shaku (尺) or 10 sun (寸). 1 sun is divided into 10 bu (分), with 1 bu roughly equal to 36 seconds in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Akatsuki kokonotsu-doki” (暁九つ時).

It was used in the Edo era. It became popular alongside the spread of Shaku-Dokei, an old Japanese clock.

In this system, 1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to the next dawn). 1 shin-koku is equivalent to 1 shaku (尺) or 10 sun (寸). Each sun is divided into 10 bu (分). Han (半) is used to divide a shin-koku in half. The time notation changes every half of han, with the first half called mawari (廻り) and the second half referred to as mae (前). 1 bu is approximately 72 seconds in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Akatsuki kokonotsu-doki” (暁九つ時).

It was used in the Aobyoshi (1840), which was the samurai's legislation in the late Edo era.

In this system, 1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to the next dawn). 1 shin-koku was equally divided into three parts called jo-koku (上刻), chu-koku (中刻), and ge-koku (下刻), respectively. Each koku is about 40 minutes in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Ne no chu-koku” (子の中刻).

It was popular and used by administrators of the Tokugawa Shogunate during the Edo era.

In this system, 1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to the next dawn). 1 shin-koku was divided into two equal parts, known as jo-koku (上刻) and chu-koku (中刻). The first half of the next shin-koku was referred to as ge-koku (下刻). Each koku is approximately 60 minutes in the present day.

In general, the shin-koku was read as a number of times of a temple bell. And twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Ne no chu-koku” (子の中刻).

It was popular and used by local administrators of the Tokugawa Shogunate during the Edo era.

1 shin-koku (辰刻) represents one-sixth of the time from dawn to dusk (or dusk to the next dawn). 1 shin-koku is equally divided in half. The first half is called ge-koku (下刻), which is contained within the previous shin-koku. The second half is called jo-koku (上刻), and the next first half is called chu-koku (中刻). Each koku is about 60 minutes in the present. This system has a time lag of about one hour.

In general, twenty-four-sekki, which is a method that divides one year into twenty-four seasons, had been used because the length of day and night will shift every day. Around midnight (12 a.m.) is referred to as “Ne no jo-koku” (子の上刻).