Kabuse okumidori - sencha for cold brew

Eastern style brewing:

Vessel: A small tea pot or houhin, ranging from 100ml - 350ml in volume
Quantity: 1g for every 30ml of water
Temperature: 70-80°C
1st brew: 60 seconds (including time to pour on the leaves and pour out to the cups)
2nd brew: 15 seconds
3rd brew: 90 seconds (or as long as you feel like)

Advanced brewing tips: Whilst sencha has a general brewing guide, every type of tea is has its individual character so once you get to know the tea you can adapt the parameters to suit the tea's and your preference. 
Pouring is an important aspect in preparing sencha, especially for the first infusion. Pour very slowly disturbing the leaves as little as possible. Often it can take up to 20 seconds to pour the hot water on the tea. Gently pour the tea out and ensure you get the final drops as this is where the deepest flavours are. 
Note that cooler water will bring out more sweetness/softness in the tea but will need slightly longer infusion to achieve a more flavoursome brew. Following this logic hotter water will bring out stronger flavours faster. Also higher tea to water ratio will give more strength.
Porcelain and glass vessels have a neutral flavour and so you will get the most 'honest' result from your brew and is very suitable for sencha.
Raw clay (unglazed) Tokoname clay teapots from Japan is highly recommend. 

Western style brewing:

Vessel: A teapot from 450ml - 950ml
Quantity: 1g for every 150ml of water
Temperature 80°C
Time: 3-5 mins

Cold brew:

Vessel: Hario cold brew bottle (750ml) or a glass jug
Quantity: 1g for every 100ml of water
Instructions: Add tea to your chosen vessel then fill up with cold water. Also sencha brews much faster in cold water than other tea types the infusion will be ready after 1 hour some sencha brew even faster!