Kokeshi - What kind of features do they have? 
Dento Kokeshi Traditional Kokeshi A traditional Yajiro Prefecture Kokeshi Nesting Doll, it is a mother with 5 children by Sato Koichi. (PIC) refers to the traditional type of Kokeshi. There are 11 strains (categories) that exist today and vary in design by region of creation (check out the strains link for a more in depth description by category). Kokeshi are made of wood, which include mizuki, pear, cherry and many others. They are made of two pieces and jointed by a wooden peg-like neck, others are made of a single piece of wood. They do not have limbs, and feature single, multiple red/green line designs or traditional Japanese types of flowers on their body.

The faces are painted in many variations depending on the location  they are made in, some dolls may be squinting, wide eyed, smiling, or frowning. The nose may be a simple vertical line, a split upside down v or a half circle nose just to name a few. The lips could be a small horizontal line, a double lip line or a tiny red dotted smudge.

Shingata Kokeshi Traditional Kokeshi A modern creative Kokeshi with a beautifully decorated umbrella by Kyoto. (PIC) refers to the Creative type of Kokeshi. These are what we would call free form designs that each artisan creates from his imagination and do not conform to a traditional pattern. Shingata Kokeshi may have an umbrella, a hat, cane or even be layered in silk fabrics. They are also made with Kimono Traditional Kokeshi A modern creative Kokeshi with Kimono style arms. These are mass produced for export no artist signature appears. (PIC) style arms and come in a variety of colors from blue, purple, green, reds and browns to almost any color you can think of.  I have seen some fashioned after lamp shades, or standing by a lamp post, Traditional Kokeshi This is an example of two kokeshi casually standing by a lamp post (PIC) even sitting on a Geta.

Shingata Kokeshi are even created for functional purposes like hair decorations, letter mailers,Traditional Kokeshi Mailer Kokeshi doll in Ainu style. A small note would be written, then rolled up and sealed with a thin strip, it would then be inserted into the Kokeshi by unscrewing the bottom wooden cap. The writter would give this Kokeshi to the postman who would deliver it. The practice is said to have stoped in the 1940s. (PIC) ear cleaners, napkin holders, toothpick holders,Traditional Kokeshi Kokeshi toothpick holder, delicate parquetry used to decorate the body which was then sealed with a glaze (PIC) etc. Check out the Doll Gallery to view some of the different Shingata Kokeshi in my collection.
Kokeshi History 
It is believed that Kokeshi came to existence in the early EDO period (1640-1868) and depending on who you ask, the story varies on why these little charming dolls were created.  I will share with you some of the stories I have come across in my search for enlightenment and let you decide which story to believe.

1. Lucky charm
2. Spiritual Significance - Blessing
2. Souvenirs /Massage tools for Onsen, (hot springs), visitors
3. Tribute to a dead child
4. Controversial - Kokeshi and Japanese infanticide

Kokeshi - A Lucky Charm 
The white dogwood tree, Mizuki (translates water-tree), is a very moist tree with a fine grain. It is the most common and popular choice of wood used by Kiji-shi. 

It is believed to be a lucky charm which prevents fires because of it's moisture, the Japanese often purchase or gift them to others as protection for their homes from fires.
Kokeshi - Spiritual Blessing 
Another belief is that Kokeshi dolls were created by well wishers who wanted to give expecting parents a gift  that would honor the child to come.
Kokeshi - Onsen Souvenirs 
A widely accepted belief is that Kokeshi were created as massage tools which could be purchased as a souvenir by the Onsen visitors.  The Kokeshi would be used to rub the shoulders of the visitors enjoying the hot springs.
Kokeshi - Tribute to a dead child 
There is a story that Kokeshi was created by a Soldier who had returned from war to find that his daughter had passed away of a childhood disease. The soldier stricken with grief went into solitude to reflect on his loss. While reflecting the soldier began to carve a piece of wood in the form of his young daughter which he then placed in his home as a tribute to his deceased daughter.