The uni-ball AIR and the missing flex 7

An unusual post for Bleistift: not pencils and not fountain pens, either.
Last week I saw the uni-ball AIR for the first time. I was in a WH Smith’s store, a chain of stationery stores in the UK. What grabbed my attention was the fact that it was being advertised as writing like a fountain pen, i.e. pressing down more should produce a wider line.

I was tempted, but a pack of two was £5.99 and a pack of three was £6.99. I didn’t really want to buy more than one of this pen for this prize, in case I don’t like them.

At home I then found a place where I could order them for £1.99, including postage. Unfortunately I didn’t realise that there’s a medium and a broad version of this pen. I bought the broad one by mistake.

Well, at least for the broad version the advertised flex effect isn’t very strong on most paper, have a look at my video, where I compare it to a Pelikan F nib.

The paper used in the video is Banditapple‘s new 4G paper.

The flex properties of this pen might be disappointing, but it is still a nice pen to write with.

A close up of the uni-ball Air

A close up of the uni-ball AIR

Since I made the video I noticed that Tesco had a lot of stationery offers.

Stationery offers in Tesco

Stationery offers in Tesco

I bought a pack of 12 uni-ball pens for £12, hoping the uni-ball AIR pens would be medium, not broad (the pack wasn’t marked) and that the medium pens have more flex, but unfortunately it turned out that the AIR pens in this pack were also broad.

12 pens for £12

12 pens for £12

You can read more about this pen at Clicky Post and Office Supply Geek.

The Uni Shift and a look at 0.4 mm leads 2

The Uni Shift 0.4mm unlocked

The Uni Shift 0.4mm unlocked

Let me start by saying: It’s all Lexikaliker’s fault.

He praised the virtues of 0.4 mm pencils, so I had to order one.

I had a look at various 0.4 mm pencils and decided to go with the Uni Shift for £7.43 from Amazon Marketplace in the UK1, in the USA it sells for $10.20, again on Amazon Marketplace …including shipping. In many online shops this pen can easily cost twice as much, though. I have no idea how the pen can be sent from Japan for such a good price.

The Uni Shift 0.4mm locked

The Uni Shift 0.4mm locked

Despite coming all the way from Japan it only took a few days before the pen arrived. The seller even remembered that I bought form him before.

0.4 mm

In theory

Well, this is my first 0.4mm pencil. You’d think 0.4mm doesn’t seem to be that different to 0.5mm, it’s just 20% smaller, but depending on how you write the difference in the graphite you lay down can easily be 30% or more.

Uni Shift 0.4mm

Here’s a little table showing the surface area you cover, depending on which angle you write with and assuming you don’t rotate the pencil(!). The spreadsheet is available as a Google Doc, so you can check the formulas I used. Please let me know if you find a mistake.

Surface area at 40°

Surface area at 40°

Assuming a writing angle of 40° a 0.5mm pencil would cover a surface area more than 50% bigger than a 0.4mm pencil, so there is quite a difference.

Uni Shift 0.4mm


In practice

…well at least that’s the theory. In reality things look a bit different. When I checked lead diameters with my caliper I got different numbers. Have a look at the table below. Note: 0.3mm and 0.35mm is used interchangeably my manufacturers.

Nominal value (mm)0.20.3/0.350.40.50.7
Measured value (mm)0.240.360.460.550.68

I am not sure whether I read about this discrepancy in the past, but when I had a look I couldn’t find any information about this on the web. Since my caliper isn’t ‘officially’ calibrated and is just for home use I won’t go into more details and speculation here, other that these might be legacy diameters manufacturers adhere to so that leads and pencil stay interchangeable.

Uni Shift 0.4mm

Using the nominal value, an 0.5mm lead used at an angle of 40° has a 50% bigger surface area than an 0.4mm lead. Using the measured values the 0.4mm lead is closer to the 0.5mm lead, but the gap to the 0.35mm lead widens, see table below.

Lead size (mm)0.350.40.5
Surface area (mm^2)(nominal diameter)
Surface area (mm^2) (measured diameter)

The main issue with 0.4mm pencils is that the choice of leads is not that big, but the excellent neox Graphite leads are available in 0.4mm.

Uni Shift 0.4mm

Uni Shift

The main purpose of the pipe lock mechanism seems to be to make the pencil pocket safe, i.e. the rigid sleeve/pipe is hidden so that it can’t damage your pocket. I guess the mechanism used in the Uni Shift makes it easier to create a pencil where the sleeve is rigid and doesn’t wobble, compared to mechanical pencils with a retractable sleeve. Easier might in this case also equate to ‘cheaper to manufacture’.

All sleeves out

All sleeves out

The mechanism that locks the lead feels a bit clumsy. I don’t find it as nice as some alternatives, shown in the video, mainly because it is more difficult to use single handedly.

I like the grip section. It is made from metal. The upper body of the pen is only plastic. Considering the price of the pen this is however not surprising.

All sleeves in

All sleeves in

The pencil is excellent value for money, at least for the price I paid. If you don’t like 0.4mm you can buy the Uni Shift in many other lead diameters, too.

Uni Shift 0.4mm and Silvine Memo Book

Price: June and July 2016
Exchange rates: July 2016

As usual please open images in a new tab to see a high resolution version. To see the video inhigh resolution please open in YouTube,

If you want to read more about Mitsubishi and it’s link to other companies with that name have a look as Estilofilos.

If you want to be amazed by Lexikaliker’s special 0.4mm pencil have a look at Sonderanfertigung and Sonderanfertigung 2.

The Uni Shift has been mentioned in The Pen Addict podcast, episode 152, at around 30 minutes. One of Brad Dowdy’s favourite mechanical pencils.

The Pen Addict and Dave have reviews of this mechanical pencil.





  1. When I bought it it was 3p more expensive: £7.46. []

Two deliveries – from Japan and Germany 2


What an exciting day. I got two deliveries, one from Japan and one from Germany.

Both seem to be XL... (Japan in green, Europe in yellow)

Both seem to be XL… (Japan in green, Europe in yellow)

The parcel from Japan was sent from Yumiko, a friend of Sean, who helped me get a few things I couldn’t order myself …including Uniqlo’s Tombow t-shirts. I was able to get the Pelikan version here in Europe, but the Tombow version is not being sold here.

I was hoping that the Japanese XL will be similar in size to the European XL, especially since the t-shirts being sold here come with English/Japanese tags, but unfortunately it turned out that the Japanese XL is at least one size smaller than the European version – so the t-shirts won’t fit unless I lose a lot of weight. I guess I should see this as my incentive to lose more weight ..but I don’t think it’s achievable for me to fit into these anytime soon.

...the tags are different though

…the tags are different though

There was also something else in the parcel. Something very special.

Special Hi-uni

Not as posh as the ones shown on Contrapuntalism, but nevertheless extremely nice. Lexikaliker had similar ones, too.


The other parcel did contain a replacement Pollux. You might remember that had problems with my first Pollux. Thanks to Lexikaliker, without whom I wouldn’t have any Pollux, I got a replacement

Here’s a quick look at the replacement Pollux.

As a comparison: the second video features a knife sharpened pencil. You can also see Staedtler’s sand paper in the second video.


A Pollux sharpened Mars Lumograph

A Pollux sharpened Mars Lumograph

Lexikaliker has a blog post about the unsharpened Mars Lumograph pencils.

Mitsubishi 7700 vs Staedtler Noris colour 9

If blog posts had soundtracks this post would play Billy Ocean’s “When the Going Gets Tough, the Tough Get Going” in the background1.

Today: a follow up of last year’s Noris colour wear and tear blog post, but this time I will compare the Staedtler Noris colour to another ‘hard’ coloured pencil: the Mitsubishi 7700.

Lexikaliker suggested that I should try the Mitsubishi 7700 after reading my first blog post about the Noris colour. He had previously suggested good coloured leads, I think it was after talking about redcircle leads, but knowing that I use coloured leads and pencils for writing he thought the Mitsubishi 7700 coloured pencils might be suitable as they are advertised as ‘hard’.

Staedtler Noris colour and Mitsubishi 7700

Mitsubishi 7700 and the price rise

I ordered my Mitsubishi 7700 in February 2015 and received them in March 2015. Back then I paid £9.82 (~$14.10; €12.90). You might have read in the news about what happened next, Lexikaliker covered this, too: End of last year Mitsubishi/uni decided to stop producing some of the 7700’s colours and prices have gone up a lot since then. Reminds me of what happened not long before that, when Hagomoro Bungu went out of business and people started hoarding their chalk ((At the time of writing a box of this chalk sells for £168.05 on Amazon.)). Well, the Mitsubishi 7700 has now more than doubled in price and the Amazon seller I bought from is currently selling a set of 12 Mitsubishi 7700 for £21.14 (~£30.30; €27.70). I wouldn’t be surprised if prices will rise even further.



So let’s have a look at how the two toughies, the Mitsubishi 7700 and the Noris colour. I will compare the red and the (light) blue pencils. Since you are reading a stationery blog I won’t go into much detail, but would just like to point out that the Noris colour is an extruded pencil, so it is manufactured in  very different way to other coloured pencils and that will probably also mean that it will have different properties, too.

The setup

First I looked at how dark/colour intense the line is that these pencils leave on paper. To do that  I sharpened the pencils so that the point of both pencils is a conical frustum (a cone without the top). Both pencils’ points/frustum’s had the same top radii. This was achieve by sharpening with a Deli 0668 where I ‘dialled’ the point adjuster back. I then used a force of 1.8 N2 and a speed of 25 mm/s to move the pencils across the paper3. The pencil had an angle of 90°, so axial pen force = normal pen force. The paper was from a Brunnen – Der grüne Block, which I have used many times before on this blog.

Staedtler Noris colour and Mitsubishi 7700

Darkness/Colour intensity

As mentioned before I compared red and blue. As my Mitsubishi 7700 set has far fewer colours than my Noris colour set I picked a colour from the Mitsubishi set and then tried to find the closest corresponding match form the Noris set, based on the colour of the pencil’s body more than based on the colour of the point.

Measuring colour intensity seems to be more complicated than expected, at least for someone like me who doesn’t know what he’s doing. I scanned the paper on my scanner with 2400 dpi, turning off all auto settings I could find and used the ‘linear’ settings for the colours. I then looked at the file with a graphics editor. The HSB values used for my Pilot neox Graphite blog post don’t seem useful here and only looking at the red and blue values alone seems slightly unfair as a different shade of red or blue might actually be darker for the eye but contain less red or blue, but it’s the best I got for now.

Visually the lines left by the Mitsubishi 7700 look darker than those from the Noris colour, but lets see whether we can measure this. I looked at a 150 pixel * 25 pixel area from each line to look at the histogram.

Come on you reds4

Let’s compare the reds. The numbers at the top are for the red channel only. Lower numbers mean it’s darker,  but the numbers are purely based on the red channel, so a shade of red that is different to the RGB red will provide numbers that should be used with caution.

Good that there’s no publication bias at Bleistift. Quite boringly the numbers confirm how it looks like anyway: the Mitsubishi creates a darker shade of red on the paper (…at least when used with 1.8 N and an angle of 90° while moving along the paper with 25 mm/s. The pencils will behave differently under different conditions).

Mitsubishi 7700 #15 RedNoris colour, a similar shade of red
Come on you blues5

Next up: the blues. I compared Mitsubishi’s #8 Light Blue to the closest Noris colour match.

Again, the Mitsubishi looks darker, but this time the numbers seem to contradict how it looks like. They seem to indicate that the blue colour of the line left by the Noris colour is a slightly darker blue. I am not sure why this is. Maybe other find the Noris colour’s line to be of a darker blue? It could be down to the Noris being a closer match to the RGB blue or to the fact that something makes the human eye/brain perceive the #8 Light Blue as darker, even though it isn’t. This time the numbers are for the blue channel.

Mitsubishi 7700 #8 Light BlueNoris colour, a similar shade of red




Wear and tear

Let’s look at how hard these pencils really are. If they are to be used for writing they should keep their point as long as possible. For this I have done a similar test as in the Noris colour wear and tear blog post. I wrote a line of text with a freshly sharpened pencil, using the Deli 0635‘s 17° angle, while trying to keep writing angle and pressure constant.

Mitsubishi’s #15 (Red) started with a

  • horizontal width of 0.3 mm and a
  • diagonal width of 0.1 mm

and ended with a vertical width of 0.5 mm.

Mitsubishi’s #8 (Light Blue) started with a

  • horizontal width of 0.3 mm and a
  • diagonal width of 0.1 mm

and ended with a vertical width of 0.4 mm.

The Noris colour red started with a

  • horizontal width of 0.3 mm and a
  • diagonal width of 0.1 mm

and ended with a vertical width of 0.4 – 0.5 mm.

The Noris colour blue started with a

  • horizontal width of 0.3 mm and a
  • diagonal width of 0.2 mm

and ended with a vertical width of 0.4 mm.

The Noris colour seems to have kept the point slightly better, but the numbers indicate that for both brands the red pencil didn’t keep the point as well as the blue pencil. As this second test was not done using a measured force it might very well be that the actual pressure used was different.

The lines produced by constant force support the idea that the Noris colour keeps the point longer, but on the constant force lines it looks as of the blue pencils, especially the Mitsubishi, was worn down more.

Staedtler Noris colour and Mitsubishi 7700


Coloured pencil are nowhere near as good at keeping their point, so they are not great for writing (surprise, surprise), but some are better than other. The Noris colour keeps its point better, but the darker lines seem to indicate that the Mitsubishi 7700 is a better choise. It is a shame that the Noris colour pencils are not labelled by colour, that would have provided another way of selecting equivalent pencils to match the 7700’s colours. In the case of the Mitsubishi 7700 vs the Staetdler Noris colour you might just pick a darker shade of red or blue for the Noris colour and get similar levels of darkness as you do from the 7700.

I had fun writing this blog post, but I realise this is not everyone’s cup of tea – the DelGuard blog post with a pressure diagram wasn’t very popular at all, so I will try to limit these kind of blog posts in the future.

A heavily scaled down version of the test sheet

A heavily scaled down version of the test sheet

Prices: Dates as explained

Exchange rates: January 2016
As usual: open the images in a new tab/window to look at them in full resolution.

  1. Please hum along if you like. I assume that won’t infringe any copyright. []
  2. With less force the lines would have been quite light. You do need to use quite a bit of force when you want to write with coloured pencils. []
  3. Actually, the pencil was stationary ;^) and I moved the paper. []
  4. No, I don’t follow football, but couldn’t resist. []
  5. No, I really don’t watch football. []

Disappointed with the Kuru Toga – again 13

Welcome to a blog post that is linked to my 2009 blog post about the Kuru Toga and is my third blog post this month about sliding sleeve pencils, after the M&G m9 and the 0.3mm Orenz.

If blog posts came with a soundtrack this post’s sound track would be Queen’s ‘Under pressure’, you’ll see why…

As mentioned previously there is a new Kuru Toga model that features a sliding sleeve – and I had to buy one.  It’s from a Japanese seller on eBay and I paid $14.09 (~£9.75; €13.00) (sorry, no link to the product as the seller doesn’t sell it anymore).

Kuru Toga Pipe Slide

About the ‘pipe’

I will call this model ‘pipe slide’ for now as there is no English version with an English name out yet and one of the only things I can read on the Japanese packaging is ‘pipe slide’ in Katakana. The name is slightly misleading as the sleeve is more of a cone than a pipe. Otherwise it looks pretty similar to the original Kuru Toga, with one of the more obvious differences being the black grip area, instead of the original silver one.

More of a cone than a pipe

More of a cone than a pipe

The idea, as with other sliding sleeve pencils, is that you can just keep writing without having to advance the lead – because the sleeve that protects the lead is sliding back further and further as you use the lead up …until you have used up the several millimetres of lead that where originally protected by the sleeve.

About the mechanism to rotate the lead

On my original Kuru Toga in 0.5mm you had to press the lead down 40 times to rotate the mechanism by 360°. The ‘pipe sleeve’ model, also 0.5mm works differently. Each pressing down of the lead will rotate the lead about twice as much as the original model, so pressing the lead down 20 times will rotate it by 360°.

Kuru Toga Pipe Slide

Does it work?

…the sleeve

Well, the sliding sleeve works. It’s not as good as the one from the Pentel Orenz or the Staedtler Microfix S, because the sleeve is more likely to press into the paper, but it will work well.

When the sleeve is partly retracted the lead will feel a bit more wobbly, but it isn’t a problem at all. You will need about 0.05 N of pressure to slide the sleeve back, which is a pretty good value, but as mentioned earlier the sleeve is more in the way, so the writing experience you get from a pencil with similar pressure requirements, like the Microfix S, is better.

…the mechanism to rotate the lead

The mechanism still doesn’t work for me, just like the original Kuru Toga, six years ago.  It does seem to work for others. This pencil is in the Pen Addict’s Top 5 and Brad wrote: “Not a gimmick either. It actually works.”, but I assume when writing he is using much more pressure than I do.

There seems to be a strange discrepancy here. Many people seem to prefer soft wood cased pencils, indicating that they might use less pressure than me when writing, but on the other hand many people seem happy with the Kuru Toga, indicating that they use more pressure than me when writing.

What is your experience with the Kuru Toga – and what kind of wood cased pencils do you prefer? I’d love to find out how they relate to each other for others. 

You need quite a bit less force or pressure to rotate the lead of the pipe slide model, 0.3 N in my case, but that’s still more than I seem to normally use. Things get even worse when you write in cursive, as there’ll the lead will be lifted and placed on the paper less often, so there are fewer opportunities to rotate the lead anyway.

Maybe that’s the reason why my Kuru Toga pipe slide came with a reasonably hard lead1, so that you press a bit harder.


It’s not a bad mechanical pencil, but unfortunately it is just not good at doing what is supposed to set it apart. I wonder whether Schmidt’s2 rotating lead apparatus would have worked any better, or Kotobuki’s mechanism…

Kuru Toga Pipe Slide


Price and exchange rates: January 2016

Please open the images in a new tab/windows to see them at full resolution.

The video is available in full resolution on YouTube.

I have added the Kuru Toga Pipe slide to my sliding sleeve table.

Michael Fryda has a YouTube review of this pencil.

  1. harder than the lead some other Japanese pencils I have came with []
  2. Not related to Lexikaliker, I think. []