Da Guan Tong Bao 1-cash large issue, Broad CAO GUAN variety
The 4 characters are larger than regular issue. The first stroke of element 艹 CAO of character 觀 GUAN is strike through to the right and hence broad. Chinese name called" GUANG CAO GUAN". Written by emperor himself in elegant Slender Gold style. Cast under rule of emperor Hui Zong of Northern Song dynasty. 25.22mm, 3.17g, small pin hole at 7 o'cock, XF. Price 20 USD @ dong_hua_zhai's Coins and Antiques
Note : Chinese coins from Northern Song dynasty (AD960 - 1127) are famous for it's beautiful Chinese calligraphy and fine quality. One interesting feature in this period is the matched coins. 2 coins in different calligraphic styles but in same period title, all dimensions, and even composition of alloy make a perfect pair . I.e. Li script vs. Seal script, Regular script vs. Seal script.