Japanese knives come in quite a spectrum of steels and tempers nowadays. I'll differentiate by hardness range
56-59 HRC types: Made from relatively soft conventional stainless, usually in a monosteel construction. These are a direct improvement of the stainless knife as we know it in the west, albeit slightly less abuse proof and geared more towards performance when used correctly. Maintenance regimes known for western knives can still be applied to some degree - rarely sharpening but rehoning often with eg aforementioned ceramic rods (some types might even still be compatible honing steels). More edge retention than even softer ones. "old school" western types can be expected - but nowadays, even some German makers make knives that fit this category.
60-64HRC types: Carbon steel, very high grade conventional stainless (like VG10, Gin-3) and so called PM steels (like SG-2) are used here, often in a laminated construction (awase or so called-damascus that is usually still an awase design).
Maintenance regime differs. Honing will be done via stropping (on paper, leather, softwood...), never with honing steel, and using ceramic rods is also not well advised here (they are slightly abrasive and can leave a rougher polish on the edge than it had before, and they can create too much punctual stress). So the escalation from stropping will involve an actual fine whetstone, which you might need more often than a "full" sharpening on a western knife. Full sharpening intervals will be longer, though, and the level of sharpness a knife can be kept at for use is quite higher with that type. These knives will not be very abuse proof, but use with board impact, eg chopping, unless done clumsily or with heavy force, is not abuse, that is what these are designed for more than western knives. Actually, using western technique (especially using walking-rocking techniques while applying significant pressure) can be worse for these.
65HRC+: Carbon or PM steel, practically always in laminated OR differentially tempered construction. Edge retention is very dependent on the cutting surface and technique used (either the edge or the board absorbs the damage, there is no more getting out of the way), as well as what "configuration" is chosen during sharpening (microbevels, angles... you need to be MORE conservative than with the category above!) - and can be extremely good or surprisingly poor. Stropping will still work but be somewhat less effective, so maintenance relies on the fine stone even more. (From my experience, with the laminated type - this likely does not apply 1:1 to differentially tempered!), if used right, these can maintain a "very decent" sharpness for an extended time, but if you want "scary sharp as fork for a reasonable time" you are better off with the 60-64HRC group.
These are knives that break before they bend, so abuse can be catastrophic.