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This one started as a routine restring sound check and turned into a five-minute rant. Fair warning: I called it a "sound check turned rant turned yap" myself. But there were two genuinely useful things buried in there — a verdict on Kizuna Z61 that people had been asking me for, and a first look at a new racket. Let me lay both out properly.

My current setup

Hybrid stringing, 27 lbs on the mains and 29 on the crosses. Exbolt 68 on the mains, and then either Kizuna Z61 or Exbolt 63 on the crosses depending on what my stringer has in stock.

If hybrid stringing is new to you: instead of one string through the whole frame, you use two different strings for the vertical mains and the horizontal crosses. The mains do most of the work on power and take most of the abuse, so a lot of players put something durable there. The crosses have more influence on feel and sound, so that is where you tune. The higher cross tension is normal — crosses sit on top and lose tension differently, so stringing them a couple of pounds higher evens out the bed.

The Kizuna verdict people were waiting for

Short version, and I did not soften it in the video: Kizuna loses tension fast.

I restring roughly every two weeks because of how often I play and how hard I train. With Exbolt, if I miss that window, the racket is usually still playable into a third week. Not ideal, and I do not enjoy it, but it works. With Kizuna I picked up a racket at around the two-week mark and it felt soft, dead and unresponsive. Genuinely bad.

So that is the trade-off. Would I still use it? Yes — if my stringer has it, I will take Kizuna Z61 over Exbolt 63 on the crosses. Z61 is slightly softer, which gives you a bit more wiggle room on smashes while staying good on drives. Exbolt 63 is marginally better on drives but noticeably worse, to my feel, on smashes. If Kizuna is not available it is not the end of the world; I just use 63 instead.

Both are responsive, both are repulsive, both have good touch, both are durable enough. It genuinely comes down to how picky you are and how often you restring.

How to tell your strings are dead

This is the part the video assumed you already knew, so here it is spelled out. Strings rarely announce themselves by breaking. They fade, and because the fade is gradual most players adapt to it without noticing and just conclude they are playing badly.

Signs to watch for: the sound goes dull and thuddy rather than crisp; clears that used to reach the back line start dropping short even though your swing feels the same; the shuttle sits in the bed a fraction too long on drives; and the string bed looks notched or has visibly shifted out of its grid.

A rough rule that has served me and most players I coach: restring as many times per year as you play per week. Twice a week, twice a year. If you are training seriously, that number goes up fast — I am on a fortnight, which is roughly twenty-six restrings a year.

The new racket: HUNDRED Nitrix 80 Bullet

Worth saying up front, because I said it in the clip too: HUNDRED sent me this as a review unit. Take that into account.

For anyone unfamiliar with how HUNDRED organise their lineup, there are three families, and they map fairly cleanly onto Yonex equivalents: Nitrix is the head-heavy attacking line, Flareon is the speed line, and Hyphonic is the control line.

The Nitrix 70s were the previous flagship, and there were two. The Volta was the more traditional head-heavy all-rounder. The 70 Venom was more flexible and built around raw power. The Nitrix 80 Bullet now sits above both as the new high end — though given the naming scheme, I would not be shocked if something numbered higher shows up eventually.

Shaft is 5.9 mm, which is thin. When they first sent it I found it a bit too stiff for where I was at. I do not expect to feel that now — my technique and my strength have both moved on since then, and I am genuinely curious how much more I can get out of it. It goes into full training rotation this coming week.

One thing worth stealing from Malaysian stringers

A small detail that had nothing to do with performance: the shop bubble-wrapped the frame and wrapped the racket properly, so there was not a single mark on it. If you are handing your racket to someone, that level of care tells you a lot about how the rest of the job was done.

The takeaway

Kizuna Z61 feels lovely and sounds livelier, but it will not hold tension for you — it suits players who restring often. Exbolt 63 is the more forgiving choice if your restrings are irregular. And whichever you pick, restring more often than you currently do. New string genuinely feels amazing, and most players are quietly playing on dead string for months.