1.  Introduction

‘InnerForce Layer ALC’ is one of the most important blades in current Butterfly blade range. It is softer and slower than ‘InnerForce Layer ZLC’ in the same ‘InnerForce Layer’ series. Because ‘InnerForce Layer ALC’ is quite close to 5-ply wood offensive blades, many top players and skilled amateur players are now trying it.

Butterfly InnerForce Layer ALC 01
Fig.01 Butterfly ‘InnerForce Layer ALC’

‘InnerForce Layer’ series which was announce in 2014 is renewed blade family which is modified from older ‘InnerForce’ series. Design of blades in ‘InnerForce’ was renewed, and head size of some models such as ‘InnerForce ZLC’ was reduced. Former model of ‘InnerForce Layer ALC’ is ‘InnerForce ALC’.

Butterfly InnerForce Layer ALC 02
Fig.02 ‘InnerForce ALC’ (left) and ‘InnerForce Layer ALC’ (right)

Fig.02 shows older ‘InnerForce ALC’ and newer ‘InnerForce Layer ALC’. There isn’t fundamental difference between those two models, except for graphic design. At the time of ‘InnerForce’ series, the appearance of ‘InnerForce ALC’ was one step cheaper than that of top model in the series – ‘InnerForce ZLC’. Instead of Aluminum nameplate of ‘InnerForce ZLC’, plastic lens of normal shape was applied for ‘InnerForce ALC’. Differently from simple design of the handle of ‘InnerForce ZLC’, somewhat strange design was applied for the handle of ‘InnerForce ALC’. However, this design strategy was changed when ‘InnerForce’ series was replaced with ‘InnerForce Layer’ series. Now the same design concept (except for coloring) as ‘InnerForce Layer ZLC’ is being applied for ‘InnerForce Layer ALC’.

The head size of ‘InnerForce ZLC’ was reduced from 158mm x 151mm to 157mm x 150mm when it was replaced with ‘InnerForce Layer ZLC’. However, the head size of ‘InnerForce ALC’ was not modified because it had already been 157mm x 150mm. ‘InnerForce Layer ALC’ just succeeded the head size of ‘InnerForce ALC’.

Butterfly InnerForce Layer ALC 03
Fig.03 Plywood constructions of ‘InnerForce Layer ALC’ (top) and ‘InnerForce ALC’ (bottom)

Fig.03 shows the plywood construction of ‘InnerForce Layer ALC’ (top) and that of ‘InnerForce ALC’ (bottom). There isn’t any difference between those two. The plywood construction of ‘InnerForce Layer ALC’ is identical to that of ‘InnerForce ALC’.


Well known ‘ALC (Arylate Carbon)’ is placed between 2nd layer (middle layer) and center layer of 5-plywood construction. Top layer is Limba. Middle layer and center layer are Ayous. Overall thickness is about 5.8mm. (It is written as 5.9mm on Butterfly catalog. But, this kind of difference between specification and actual product can usually occur in blade construction.)

Butterfly InnerForce Layer ALC 04
Fig.04 FL handle (left) and ST handle (right) of ‘InnerForce Layer ALC’

The FL (flared) handle of ‘InnerForce Layer ALC’ is similar to that of ‘Timo Boll’ series. It is different from the FL handle of ‘Zhang Jike’ series which is a bit wider and a bit flatter. Therefore the cross section of the FL handle of ‘InnerForce Layer ALC’ is narrow and tall. The width of FL handle at the middle of handle is about 26mm. European adult players with big hand may feel that it is too narrow. In that case, ST handle is recommended.

The ST (straight) handle of ‘InnerForce Layer ALC’ is similar to that of ‘Zhang Jike’ series. The cross section of it is a much more rounded than that of ‘Timo Boll’ series which is squared. Width of ST handle is about 28mm. Although we can’t say that it is ‘wide’, the player with big hand can grip it without problem.

Butterfly InnerForce Layer ALC 05
Fig.05 Backside of ‘InnerForce Layer ALC’

Fig.05 shows the backside of ‘InnerForce Layer ALC’. Differently from older ‘InnerForce ALC’, there isn’t any printing on the backside face of ‘InnerForce Layer ALC’.

At low place of handle, there is small rounded lens which includes hologram. This hologram lens started to be applied to all Butterfly blades from 2014. Maybe there are some customers who don’t like this new hologram lens but likes older bigger rounded lens which includes the name of fiber. However, at least for this model – ‘InnerForce Layer ALC’, the new hologram lens looks doesn’t look bad. The simple graphic of the handle of ‘InnerForce Layer’ series fits well for small hologram lens. (But, I don’t like the hologram lens on the backside of Zhang Jike series because the handle graphic of Zhang Jike series is not as simple as that of ‘InnerForce Layer’ series.)


Then let’s examine the characteristics of ‘InnerForce Layer ALC’ by ‘Performance Indices’ and compare it with some other models in the market.


2. Blades to be compared

Following blades will be compared with ‘InnerForce Layer ALC’.

  • Stiga Allround Classic – Reference for Performance Indices
  • Butterfly InnerForce Layer ZLC
  • Butterfly Timo Boll ALC
  • Tibhar Stratus Samsonov Carbon
  • Stiga Offensive Classic Carbon
  • Butterfly Korbel


‘Allround Classic’ is the representative of traditional all-round blades. And, it is the reference blade of Performance Indices in TTGear Lab. All indices for ‘Allround Classic’ is 1.0.

‘InnerForce Layer ZLC’ is the representative model of ‘InnerForce Layer’ series. Its construction is similar to that of ‘InnerForce Layer ALC’. But, its fiber is different from ‘InnerForce Layer ALC’, and it is a bit thicker than ‘InnerForce Layer ALC’.

‘Timo Boll ALC’ is very famous blade whose fiber is ‘ALC’. Differently from ‘inner fiber’ construction of ‘InnerForce Layer ALC’, its fiber is placed directly under top layer. We can call that kind of construction as ‘outer fiber’ construction.

‘Stratus Samsonov Carbon’ and ‘Offensive Classic Carbon’ can be also compared with ‘InnerForce Layer ALC’ because those two are also the blades with ‘inner fiber’ construction. Especially ‘Stratus Samsonov Carbon’ looks similar to ‘InnerForce Layer ALC’. However, its center layer is softer than that of ‘InnerForce Layer ALC’.

‘Korbel’ is the representative 5-ply wood offensive blade. It is important in this comparison because most of ‘inner fiber’ blades are being selected as the replacement of 5-ply wood offensive blades such as ‘Korbel’, in this ‘poly ball’ age.


Comparison will be done by performance indices. Concerning the detail of four performance indices, please refer to following articles in ‘Background’ section :


3. Comparison by Performance Indices

Butterfly InnerForce Layer ALC 06
Fig.06 Comparison by Elasticity Indices

Fig.06 shows the comparison graph of Elasticity Indices

Ep (Primary Elasticity Index) is directly concerned with the rebound speed of blade. Ec (Central Elasticity Index) is concerned with additional ‘kick’ when player hits ball very hard.

Ep and Ec of ‘InnerForce Layer ALC’ are 1.62 and 1.45 respectively. Its Ep (= 1.62) is higher than Ep of Korbel (= 1.54) which is a widely used 5-ply wood offensive blade. But, the difference isn’t big. Its Ec (= 1.45) is also higher than that of Korbel (= 1.27).

‘InnerForce Layer ZLC’ shows higher values of Ep and Ec (= 1.90 and 1.73 respectively) than ‘InnerForce Layer ALC’. That is because of the difference of fiber material. ‘Timo Boll ALC’ shows even higher values (Ep = 2.14, Ec = 1.77). That is because the distance between fiber and fiber in the construction of ‘Timo Boll ALC’ is bigger the distance between fiber and fiber in ‘inner fiber’ construction. If we think only about elasticity,  ‘outer fiber’ construction such as that of ‘Timo Boll ALC’ is much more effective than ‘inner fiber’ construction. Nevertheless we know that ‘inner fiber’ construction is meaningful because elasticity is not everything of table tennis blade. Softer and more natural feeling is sometimes more important than elasticity.

Although its construction looks similar to that of ‘InnerForce Layer ALC’, ‘Stratus Samsonov Carbon’ shows noticeably lower values of Ep and Ec (= 1.32 and 1.24 respectively). That is because its center layer is Kiri which is softer that Ayous which is the center layer of ‘InnerForce Layer ALC’.

‘Offensive Classic Carbon’ also shows noticeably lower values of Ep and Ec (= 1.40 and 1.14 respectively) although its center layer is the same Ayous as the center layer of ‘InnerForce Layer ALC’. That is because ‘Carbon Fleece’ which is the fiber of ‘Offensive Classic Carbon’ is much softer and much less elastic than ‘ALC’.


Examining Ec/Ep is also a easier way to understand the tendency of elasticity of blades. Fig.07 shows the relationship between Ec/Ep and Ep.

Butterfly InnerForce Layer ALC 07
Fig.07 Ec/Ep vs. Ep

Ec/Ep expresses the ‘tendency’ of the elasticity of blade. By examining Ec/Ep and Ep at the same time, we can easily understand the behavior of blades.

On the graph, all the blades in this comparison except for reference blade are in the range of Ec/Ep < 1.0, i.e. ‘Hold’ range. ‘InnerForce Layer ALC’ is on the border between ‘Mild Hold’ range and ‘Deep Hold’ range. If we compare its characteristic with ‘Korbel’, ‘InnerForce Layer ALC’ is a bit faster and holds ball one step less than ‘Korbel’ when player hits ball very hard.

Although ‘InnerForce Layer ALC’ is somewhat different from ‘Korbel’, it is relatively close  to ‘Korbel’ on the graph when it is compared with ‘InnerForce ZLC’ and ‘Timo Ball ALC’. It means that relatively less effort is needed when player tries to replace 5-ply wood offensive blade such as ‘Korbel’ with ‘InnerForce Layer ALC’.

If we just think about the ease of replacement from ‘Korbel’, ‘Offensive Classic Carbon’ made be better choice because it is placed very close to ‘Korbel’. And, ‘Timo Boll ALC’ shows very similar Ec/Ep as ‘Korbel’ and provides much higher rebound. However, the primary elasticity of ‘Offensive Classic Carbon’ is not higher than that of ‘Korbel’, and ‘Timo Boll ALC’ may be too fast for the players who have used ‘Korbel’ or 5-ply wood offensive blades with similar speed level as ‘Korbel’ for long time.

If what we want is small but certain increase of power, ‘InnerForce Layer ALC’ may be optimum choice because it provides a bit higher speed and one step higher kick than ‘Korbel’. Also, if we only think about elasticity, we may be able to recommend ‘InnerForce Layer ZLC’ to the players who want one step higher speed than ‘InnerForce Layer ALC’. But, we have to also check Vibration Indices before that recommendation.


Then successively, let’s compare Vibration Indices. Fig. 08 shows the comparison graph of Vibration Indices.

Butterfly InnerForce Layer ALC 08
Fig.08 Comparison by Vibration Indices

Vibration Indices are concerned with feeling. Vp indicates primary feeling which is transferred to player’s palm. And, Vl is the feeling at the wing of a blade. It is felt by player’s index finger or middle finger.

The Vp and Vl of ‘InnerForce Layer ALC’ are 1.15 and 1.23 respectively. The blade whose Vp is the closest to that of ‘InnerForce Layer ALC’ is ‘Stratus Samsonov Carbon’ (Vp = 1.11). The Vl of ‘Stratus Samsonov Carbon’ (= 1.25) is also very close to that of ‘InnerForce Layer ALC’. (However, on the graph ‘Stratus Samsonov Carbon’ looks somewhat different from ‘InnerForce Layer ALC’ because its Vp is smaller but its Vl is bigger than those of ‘InnerForce Layer ALC’. )

‘InnerForce Layer ZLC’ and ‘Timo Boll ALC’ show higher primary Vibration Indices than ‘InnerForce Layer ALC’. (Vp’s are 1.24 and 1.26 respectively.) It coincides with our expectation because ‘InnerForce Layer ZLC’ is equipped with harder fiber, and the span between two ALC layers of ‘Timo Boll ALC’ is bigger than that of ‘InnerForce Layer ALC’. But, the Vl of ‘InnerForce Layer ZLC’ (= 1.21) is a bit smaller than that of ‘InnerForce Layer ALC’ (= 1.23) while the Vl of ‘Timo Boll ALC’ (= 1.41) is much bigger than that of ‘InnerForce ALC’. Because the difference of 0.02 is almost ignorable, we can think that ‘InnerForce ALC’ and ‘InnerForce ZLC’ provide almost identical feeling to the fingertip of index finger. From this result, we can consider that the kind of fiber material gives less influence to the feeling at index finger if the construction of blade is ‘inner fiber’ construction. It is even more apparent if we examine the Vl’s of three other blades – ‘Stratus Samsonov Carbon’, ‘Offensive Classic Carbon’ and ‘Korbel’. The Vl’s of those three blades (1.25, 1.26 and 1.23 respectably) are also very close to those of ‘InnerForce Layer ALC’ and ‘InnerForce Layer ZLC’, while Vp’s of those blades show much more difference.

By the examination of Vibration Indices, we can see that the primary feeling of ‘InnerForce Layer ALC’ is just a bit harder than that of  ‘Korbel’ which is the representative of offensive 5-ply wood blades, and that the fiber blades with ‘inner fiber’ construction under this comparison provide similar feeling with ‘Korbel’ at the fingertip of index finger.


Examining Vl/Vp is easier way for the comparison of the tendency of feeling. Fig.09 shows the relationship between Vl/Vp and Vp for easier comparison.

Butterfly InnerForce Layer ALC 09
Fig.09 Vl/Vp vs. Vp

On the graph of Vl/Vp, all the blades except ‘Allround Classic’ (which is reference blade whose values are fixed as 1.0) and ‘InnerForce Layer ZLC’ are placed in the range that Vl/Vp > 1.0. Being placed at the range that Vl/Vp > 1.0 means that the feeling of blade is relatively sharper at fingertip (of index finger) and relatively softer at palm. If we don’t think about reference blade, all the blades in this comparison except for ‘InnerForce Layer ZLC’ provides relatively sharper feeling at index finger than at palm. That is very important characteristic of ‘Korbel’ which is the representative of 5-ply wood offensive blade.

Some players select ‘InnerForce Layer ZLC’ as the replacement of ‘Korbel’ for getting more power. However, at least we consider the issue of feeling, ‘InnerForce Layer ZLC’ is placed somewhat far from Korbel. Players may feel that ‘InnerForce Layer ZLC’ is similar to 7-ply wood blades such as ‘Clipper CR’. On the contrary, ‘InnerForce Layer ALC’ is placed in the same ‘sharper at index finger’ range as ‘Korbel’ on the graph. Strictly speaking, on the graph ‘InnerForce Layer ALC’ is placed in between ‘InnerForce Layer ZLC’ and ‘Korbel’. We can consider that ‘InnerForce Layer ALC’ may be better choice than ‘InnerForce Layer ZLC’ if we need the replacement of ‘Korbel’ and feeling is very important issue.

If we just consider feeling, ‘Offensive Classic Carbon’ or ‘Stratus Samsonov Carbon’ can be better choice than ‘InnerForce Layer ALC’ because those two are placed near ‘Korbel’ on the graph. And, if we just consider Vl/Vp, ‘Timo Boll ALC’ can also be very good choice for the replacement of ‘Korbel’. (And, Ec/Ep of ‘Timo Boll ALC’ is also very close to that of ‘Korbel’.) However, for some players who have been accustomed to 5-ply wood offensive blades ‘Timo Boll ALC’ may be too hard. (Vp of ‘Timo Boll ALC’ is much higher than that of ‘Korbel’.)

‘InnerForce Layer ALC’ may be optimum choice if we can accept that it provides noticeably less sharp feeling at index finger than ‘Korbel’. Therefore, ‘InnerForce Layer ALC’ is not as exciting as ‘Korbel’. But, although the level of sharpness is low, anyway ‘InnerForce Layer ALC’ is still in ‘relatively sharp at index finger’ range. And, primary feeling of ‘InnerForce Layer ALC’ is one step harder than that of ‘Korbel’. But, ‘InnerForce Layer ALC’ is not as hard as ‘Timo Boll ALC’. That may be the optimum feeling of a blade which replaces 5-ply wood offensive blade such as ‘Korbel’ for surviving poly-ball age.


Butterfly InnerForce Layer ALC 10


4. Summary

The result of comparison can be summarized as follows :

  • On comparison graphs, ‘InnerForce Layer ALC’ is placed roughly in between ‘InnerForce Layer ZLC’ and ‘Korbel’.
  • ‘InnerForce Layer ALC’ is one step slower than ‘InnerForce Layer ZLC’. And, it is noticeably slower than ‘Timo Boll ALC’ which is equipped with same ‘ALC’ material. But, it is a bit faster than typical 5-ply wood offensive blade such as famous ‘Korbel’, and at the center of blade head it is more elastic than ‘Korbel.
  • Primary feeling of ‘InnerForce Layer ALC’ is a bit harder than that of ‘Korbel’ which is the representative of 5-ply wood offensive blades. But, the primary feeling of ‘InnerForce Layer ALC’ is much softer than that of ‘Timo Boll ALC’ whose fiber material is same as that of ‘InnerForce Layer ALC’ but placed one step outward. The ‘inner fiber’ construction of ‘InnerForce Layer ALC’ makes this advantage.
  • All ‘inner fiber’ blades in this comparison provide similar level of feeling at index finger to the feeling of ‘Korbel’ which is the representative of 5-ply wood offensive blade. It may be one of important characteristics of ‘inner fiber’ construction.

Some players may feel that ‘InnerForce Layer ALC’ is too common, and is less distinctive than ‘InnerForce ZLC’ or ‘Timo Boll ALC’. It is not as fast as ‘InnerForce ZLC’ or ‘Timo Boll ALC’. And, it doesn’t hold ball as deep as ‘Offensive Classic Carbon’ and ‘Timo Boll ALC’. Also, although it provides sharp feeling at index finger, that feeling is not as sharp (or exiting) as that of ‘Korbel’, ‘Stratus Samsonov Carbon’, ‘Timo Boll ALC’ and ‘Offensive Classic Carbon’. However, if we don’t want sudden change of blade, and just want a bit improved power from 5-ply wood offensive blade such as ‘Korbel’ for surviving poly-ball age, ‘InnerForce Layer ALC’ may be the optimum blade that can provide what we want.

Butterfly InnerForce Layer ALC 11



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