REVIEW: ASICS Skysensor and Tarther Japan

The Japan series of ASICS shoes enjoy the kind of loyal following unheard of among other sports brands, to the extent that everything underfoot (i.e. midsole and outsole) have remained largely unadulterated for over a decade. After all, you don’t fix what isn’t broken. The Japan series shoes are in fact made in Japan; everything from overlays to SpEVA foam production. This is in contrast to their mass market shoes which are mostly made in China.

I was very excited to try out these two shoes because they were supposed to have a bouncier and more responsive feel compared to their non-Japan equivalents, i.e. Skysensor Glide and Tartherzeal. 
The main thing that puts people off is probably the price. The MSRP of the Skysensor is S$399 and that of the Tarther Japan is S$369 a pair. That is exceedingly exorbitant for running shoes, by any stretch of the imagination, though it is rumoured that the retail price might be dropped to a more competitive price point in the near future.

Both the Skysensor and the Tarther are near identical in construct, the main difference being in the outsole, and therefore they are near identical in terms of weight and fit. I have now put in enough miles in both shoes to discern the subtle ride differences between these two shoes.

Both Skysensor and Tarther come in at very competitive weights, and they have a drop of 10mm at the midsole. ASICS tends not to focus on stack height (aka heel-toe drop) because the drop is dependent on shoe size, i.e. a small shoe will have a lower drop then a larger size. This is a geometrical inevitability, though other brands prefer to use a standardized US9 for measurements. It's just different ways of standardizing measurements. 

Both shoes use the exact same last and upper construct, and so I will discuss them as one shoe. The first thing you will notice is that the upper is relatively high volume, especially compared to other ASICS shoes in the same category e.g. Tartherzeal. I have low arches and relatively wide feet, and I feel that I can confidently tighten down the laces without experiencing any discomfort in my mid-foot in both these shoes. 
The upper of these shoes is composed of a very breathable mesh that does an excellent job of venting the feet, and it does this without feeling flimsy or overly compromising the overall structure of the shoe. 

Even the tongue is sufficiently padded to prevent any irritation from the laces. 

There relative lack of overlays at the forefoot areas, combined with the large shoe volume allows for plenty of room for the toes to splay naturally during the gait cycle. The majority of the overlays are composed of smooth suede fabrics that give a very luxurious feel, while at the same time I subconsciously tried hard not to get them overly dirty during my runs. 

The heel counter felt slightly roomier than the typical Tartherzeal/DS Racer heel counter as well though it did seem to have a bit more padding, but nothing that some attention to lacing couldn’t take care of.

I should add that the models I got are the “regular” width version, and a “slim” and “wide” version is available to cater for different preferences in terms of forefoot width. Note that in Japan, “wide” does not equate to a 2E width shoe; these shoes have a wider forefoot but the same width heel and midfoot across the board, and the same applies to the “slim” version.

One thing I noted, and this appears to be true for the few shoes I bought from Japan, is that the shoes tend to come with cotton laces. Cotton laces have their pros and cons in my book. On the plus side, they have an inherently higher friction surface so that when you tighten the laces, they tend not to come undone, and this gets better when they get damp from water/sweat. Their main downside is that there is a higher tendency to pick up sweaty odours over time, they weight somewhat heavier than their synthetic counterparts, and they are firmly in the inelastic category. I think cotton laces probably work very well in a cool temperate climate, but may be worth swapping out for the heat and humidity that we face in Singapore. 

It did take me a few runs and modifications to get the right fit for these shoes. One of the things that worked for me was swapping out the stock insole for a more padded one. The stock insole is a minimalist one with nicely interspersed ventilation wells, and might well be the preferred choice for race day use, but for my purposes as an uptempo and longer run shoe, I preferred a more padded insole. The more padded insole also served to reduce the shoe volume a little and offer a more snug fit. One thing you can make out from the insole is that this shoe works very well for people with low arches, which is difficult to find among racing shoes. 


Both Skysensor and Tarther Japan use the same midsole compound, which is a form of full-length SpEVA foam. This foam appears to be denser than the foam used in the Tartherzeal, and offers a more bouncy and responsive feel. Denser foam is more durable, but also heavier, and that accounts in part for a slightly heavier weight of the Tarther Japan when compared to a Tartherzeal. 

One big difference between your regular Tartherzeal and the Skysensor/ Tarther Japan is that there is a gel capsule in the heel of the Japan models, while the non-Japan models do not. This adds a little more cushioning in the heel.

One slight difference I noted between the Skysensor and the Tarther is that in the midfoot section, the Tarther has had more of the foam removed and replaced by a plastic bridge that serves to stabilze the arch. This, I believe, accounts for part of the weight difference between the Skysensor and the Tarther. This feature is also seen in quite a few of the Sortie and DS racer models. The drawback of this is the lack of full ground contact, which may or may not be of much consequent for the fast paced running this shoe is designed for.


The Tarther Japan uses a typical combination of polyurethane contact points (coined DuoSole by ASICS) in the forefoot and carbon-injected rubber in the heel. This combination is seen in quite number of their racing models, and provides excellent forefoot traction for toe-off
and good durability in the heel. DuoSole is a dense and firm compound and gives a solid ground feel, though this is muted somewhat by the ample SpEVA midsole foam in the heel.

Contrast this to the Skysensor Japan, which adopts a blown rubber approach for most of the fore- and mid-foot coverage, and defaulting again to carbon-injected rubber for the high wear heel region.


Note the toespring of the Tarther Japan
What these differences translate to in real-time, is greater forefoot traction but also less durability for the Tarther, while the Skysensor provides more wear life with its blown rubber outsole. Another thing I noted is that the Skysensor feels less flexible underfoot than the Tarther, which flexes more easily in the midfoot and forefoot section. I put this down to A) the blown rubber on the skysensor making the shoe more rigid, and B) the thicker midfoot SpEVA foam in the Skysensor midfoot (vs the cut-out seen in the Tarther). Beyond these subtle differences, both shoes feel very similar in terms of cushioning. Both have a very smooth heel to forefoot transition especially at faster tempo paces, and the greater forefoot traction of the Tarther really shines through once you get to <4:00 pace. 

The only minor drawback of these shoes is that they can feel rather firm when used for slower, longer runs, more so for the Tarther than the Skysensor. That said, these two models were designed as uptempo trainers/racers and should be judged as such. If you could only have one do-it-all type of shoe, then the Skysensor Japan is probably your best bet, as it can handle a wide range of paces and affords better durability. For a long distance racing shoe, the Tarther Japan is a better choice, simply because the better flexibility and forefoot traction tends to give a racier feel.

After about 200km in the Skysensor Japan, you can see there is some wear on the red blown rubber lugs but by and large, there is still plenty of outsole rubber left and i fully expect another 3-400km in the shoes easily, which is more than what one would reasonably expect from a lightweight racer/trainer.


The 220-230g range is extremely competitive, and is the sweet spot for marathon racers, for which these two shoes are prime candidates. Other shoes within this weight range include the Adidas Adios Boost, Mizuno Wave Hitogami, Nike Flyknit Lunar3 and the NB Fresh Foam Zante. Ultimately everyone has their preferred firmness of shoe for racing. Within this list, the Hitogami is the firmest, and the Flyknit Lunar3 is the softest. The Skysensor/Tarther sit somewhere in the middle of this spectrum. If you are looking for a durable lightweight trainer or marathon racer, this could be the shoe for you, especially if you desire a shoe without too much arch structure and higher shoe volume.  


  1. Really awesome. I'm browsing the ASICS Japan website and was amazed by their racing flat lineup. Their wide version (wide forefoot/same heel) seems perfect to my feet.

    Thanks for reviewing such nice (and rare) shoes.

  2. I bought 2 pairs of Japan Tarther in Japan at 150 SGD each which is MRSP. We are getting ripped off in Singaoire

    1. sorry i missed this comment. I think in Japan the MSRP is closer to S$200, but yes local prices are quite steep. I am told that ASICS Singapore are planning to revise the retail prices to be more in line with the prices in Japan. We will have to wait and see

  3. how do u compare tartherzeal vs tarther?

  4. how do u compare tartherzeal vs tarther?

    1. These are very different shoes. The tarther will feel more like a lightweight trainer compared to the Tartherzeal. Almost 50% difference in weight. Tartherzeal at 170+g vs Tarther at 220g.

  5. Thanks for sharing your great experience! I am so happy and aggree with you. Please keep up it in future! Hedge Trimmer Reviews

  6. Thank you so much for your reviews. So hard to find any infos of these bad boys, the Godzilla of running world, it's like comparing them to Nissan GTR the super car killers. Skysensor the breaking 2 and 4% zoomfly killer? .....Yuki Kawauchi.


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