I decide to start my journey by this one.
Han Sword(Han Jian) is just a part of Chinese Arms; mainly reflects the style of Han Dynasty.
A Han sword may have 4 edges,6 edges or 8 edges.
Its length ranges from 50 cm to 140 cm.(one of sword's nickname in Chinese is"三尺",3 Chi≈100cm)
A good Han sword must be straight,with both hardness and toughness;Apart from its practicality, in ancient times waring a sword is a fashion,and encourages a valiant spirit.
According to the old legends,:刘邦Liu Bang killed a white snake monster with a red sword,then Liu became Emperor Han Gaozu,the first emperor of the Han Dynasty.that sword is known as ChiXiao赤霄剑.(just like the Sword in the Stone and King Arthur?:-D)
Patterns on Han sword can be
twisted herb pattern(卷草纹)
corn pattern(谷纹,not sure about this translation)
an 8 edges Han Sword by 正武堂
my 4 edges Han Sword photos here↓
Tang Knife(Tang Dao),actually i haven't known much about it;
according to my memory,Tang Knife is a modified Turkic Knife(and Japanese knife/Nihontou is a modified Tang knife);
two kinds of TangDao head
BTW:↓a knife used by Zhang Qiling张起灵( a character in an interesting Chinese Novel 《盗墓笔记》Notebook of Grave-robbery)
↓the 7 swords in the movie 七剑/Seven Swords directed by 徐克Tsui Hark