Heian and Kamakura-period furniture workshop (established in temples and various government bodies); Edo-period office which administered tenders for arms, armor, etc.
Examples (6 in total)
何かさいくしているに違いない。
They must have rigged something.
その瓶も凝ったさいくでしょう?
That bottle has intricate craftsmanship, doesn't it?