四分律行事鈔資持記 2.1315

2.1315

次科，出古算中。彼謂年滿月不滿方開增算，故取極小須十八年二日也。便以等者，疏文甚詳，此不細錄；但約四位直示算法，初算胎法；大約道俗文典，九月為胎，以胎中七日一轉如五王經七七日成人，如是總有三十八轉，一轉七日，總二百六十六日。（五大四小共得九月。）自此已前，與母同氣；爾後四日，將欲趣產，與母別氣；約準成月，則九月四日通前十八年九月六日。二算閏法，大略為言，十九為章（謂十九年為一大段），以七為閏（十九年中有七閏月），三年一閏有三（初中後共九年），五年再閏有四（兩中間十年），故有七也；計前十八年九月六日一章，猶少兩月二十四日，不滿十九年；準得六月二十七日閏，通前十九年四月三日也。三頻大法，總張前年，成二百三十二月三日；頻大之法，四十九月為章，一章有三頻大，初兩十七月各有一大次，十五月有一大；如是周而復始，則用前一百九十六月成四章，一章有三日，總得十二日；餘三十六月得兩頻大，成十四日，通前成十九年四月十七日也。四布薩法，通以十四日布薩，謂抽大月布薩日數為歲；一年除閏，六大得十二日，六小得六日，準得十八日；通計十九年四月，抽得三百四十八日；用二十八日為月，則三百三十六日為一年，餘十二日在；帖前居零十七日，則成一月一日；通前則為二十年五月一日，故云長也。上是出古謬解。

The next section brings out the ancient calculations. They considered that only when the years are complete but the months are incomplete is an increased count permitted; hence, to take the minimum, it requires eighteen years and two days. Regarding "and then with..." and so forth: the text of the Commentary is very detailed, and is not recorded in detail here; it simply directly indicates the calculation methods according to the four positions. First, the method of calculating the womb: generally in secular and Buddhist texts, nine months constitute the womb; since in the womb there is one transformation every seven days, like the Sūtra of the Five Kings where one becomes a human after seven times seven days, thus there are thirty-eight transformations in total; each transformation is seven days, totaling 266 days (five long and four short months together make nine months). Prior to this, one shares the mother's qi; thereafter for four days, approaching delivery, one's qi separates from the mother's; converting this to months, it is nine months and four days, which, added to the previous [eighteen years and two days], makes eighteen years, nine months, and six days. Second, the method of calculating intercalary months: broadly speaking, nineteen makes an epoch (meaning nineteen years make one large division), taking seven as intercalations (there are seven intercalary months in nineteen years); an intercalation every three years occurs three times (the beginning, middle, and end make nine years in total); two intercalations in five years occurs four times (the two middle intervals make ten years), hence there are seven; calculating from the previous epoch of eighteen years, nine months, and six days, it still lacks two months and twenty-four days, not completing nineteen years; standardizing this yields six months and twenty-seven intercalary days, which, added to the previous, makes nineteen years, four months, and three days. Third, the method of consecutive long months: summing up the previous years, it makes 232 months and three days; in the method of consecutive long months, forty-nine months make an epoch; one epoch has three consecutive long months, the first two at seventeen months each having one long month, and the next at fifteen months having one long month; repeating this cycle, using the previous 196 months makes four epochs; one epoch has three days, totaling twelve days; the remaining thirty-six months obtain two consecutive long months, making fourteen days, which, added to the previous, makes nineteen years, four months, and seventeen days. Fourth, the method of poṣadha: universally using the fourteen-day poṣadha, this means extracting the number of poṣadha days from the long months to make up years; in one year, excluding intercalations, six long months yield twelve days, and six short months yield six days, standardizing to eighteen days; calculating through nineteen years and four months, 348 days are extracted; using twenty-eight days as a month, 336 days make one year, with twelve days remaining; adding this to the previously remaining seventeen days makes one month and one day; added to the previous, it becomes twenty years, five months, and one day, hence it is called "surplus." The above brings out the erroneous explanations of the ancients.