The ancient book records that "Lu Banchi is one foot, four inches and four minutes, eight inches between feet, and one inch is accurate and one inch is eight minutes." The "bending ruler" is a carpenter's ruler used by ancient carpenters, and its length is the same as that of the building ruler promulgated by the Ministry of Industry of the imperial court in previous dynasties. Because the building in Ming and Qing Dynasties is 32 cm long, Lu Banchi is 46.08 cm long, and Lu Banchi is 5.76 cm per inch. There are very few Lubanchi handed down from generation to generation. The Palace Museum in Beijing has a Lu Banchi, 46 cm long, which is very close to the length of Lu Banchi recorded in ancient books.
At present, there are two kinds of popular Lu Banchi in China, one is 42.9 cm and the other is 50.4 cm. At present, Lu Banchi with 42.9 cm constraint is the most widely used. However, the length of these two kinds of Lu half-feet is different from that of ancient Lu half-feet, so it can be said that these two kinds of Lu half-feet are inaccurate.
Second, the fast calculation method of Lubanchi
(1) Unit conversion:
1 half a foot = 1.44 feet (this is a special unit of length! )
1 half a foot = 1.368 feet;
1 half a foot =45.6 cm;
(Because 1 ruler =33.333 cm, 1.368 ruler *33.333 cm =45.59 cm)
There are 8 words in a row, "1 wealth, 2 diseases, 3 divorces, 4 righteousness, 5 officials, 6 robberies, 7 harms and 8 books", and the spacing between each word is 1.44/8=0. 18 (building scale).
The second line has 32 words, that is, every eight words are divided into four words, and the spacing between each word is 1/4=0.25 (which can be regarded as the unit of building inches).
Note: the number 0. 18 is used to find the specific position of a line of eight words; The number 0.25 is used to find the specific position of 32 words in the second line.
(2) Lubanchi's solution:
Convert the measurement object to feet.
Object (ruler)/0.18 = x1.x2.
The solution of the first line of eight characters
X1/8 = y1y2 (y1w is the number of digital rulers. Y2w is the remainder)
If there is no remainder, the position is y 1+ 1= position.
If the remainder is y2, it will fall into position y2+ 1= fall into position.
The solution of the second row landing
X2 Each cell is 1/4=0.25, and each of the eight words has four cells.
The corresponding relationship is:
A0 to 0.25
B0.25 to 0.5
C0.5 to 0.75
D0.75 to 1
For example, the width of the door is four feet three inches and six minutes. Is the door auspicious?
4.36/0. 18=24.222
The first row: 24/8=3 (stool)
Then 3+ 1 (one grid) =0 wealth.
Then the door is in the 0 financial position.
The second line: 0.222 between A0 and 0.25 is Cai De.
Draw a conclusion: "Wealth for men and women" is auspicious.